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ANSYS CFX Reference GuideANSYS, Inc. Southpointe 275 Technology Drive Canonsburg, PA 15317 [email protected] http://www.ansys.com (T) 724-746-3304 (F) 724-514-9494 Release 12.1 November 2009 ANSYS, Inc. is certified to ISO 9001:2008. Copyright and Trademark Information © 2009 ANSYS, Inc. All rights reserved. Unauthorized use, distribution, or duplication is prohibited. ANSYS, ANSYS Workbench, Ansoft, AUTODYN, EKM, Engineering Knowledge Manager, CFX, FLUENT, HFSS and any and all ANSYS, Inc. brand, product, service and feature names, logos and slogans are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries in the United States or other countries. ICEM CFD is a trademark used by ANSYS, Inc. under license. CFX is a trademark of Sony Corporation in Japan. All other brand, product, service and feature names or trademarks are the property of their respective owners. Disclaimer Notice THIS ANSYS SOFTWARE PRODUCT AND PROGRAM DOCUMENTATION INCLUDE TRADE SECRETS AND ARE CONFIDENTIAL AND PROPRIETARY PRODUCTS OF ANSYS, INC., ITS SUBSIDIARIES, OR LICENSORS. The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affiliates under a software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, compliance with exporting laws, warranties, disclaimers, limitations of liability, and remedies, and other provisions. The software products and documentation may be used, disclosed, transferred, or copied only in accordance with the terms and conditions of that software license agreement. ANSYS, Inc. is certified to ISO 9001:2008. ANSYS UK Ltd. is a UL registered ISO 9001:2000 company. U.S. Government Rights For U.S. Government users, except as specifically granted by the ANSYS, Inc. software license agreement, the use, duplication, or disclosure by the United States Government is subject to restrictions stated in the ANSYS, Inc. software license agreement and FAR 12.212 (for non-DOD licenses). Third-Party Software See the legal information in the product help files for the complete Legal Notice for ANSYS proprietary software and third-party software. If you are unable to access the Legal Notice, please contact ANSYS, Inc. Published in the U.S.A. 2 Table of Contents 1. CFX Launcher ............................................................................................................................................. 1 The Launcher Interface ..................................................................................................................... 1 Menu Bar ....................................................................................................................................... 1 Tool Bar ........................................................................................................................................ 3 Working Directory Selector ............................................................................................................... 3 Output Window ............................................................................................................................... 4 Customizing the Launcher ................................................................................................................. 4 CCL Structure ................................................................................................................................. 4 Example: Adding the Windows Calculator ............................................................................................ 7 2. Volume Mesh Import API ............................................................................................................................... 9 Valid Mesh Elements in CFX ............................................................................................................. 9 Creating a Custom Mesh Import Executable for CFX-Pre ...................................................................... 10 Compiling Code with the Mesh Import API ......................................................................................... 10 Linking Code with the Mesh Import API ............................................................................................ 11 Details of the Mesh Import API ........................................................................................................ 12 Defined Constants .......................................................................................................................... 12 Initialization Routines ..................................................................................................................... 13 Termination Routines ...................................................................................................................... 13 Error Handling Routines .................................................................................................................. 14 Node Routines ............................................................................................................................... 15 Element Routines ........................................................................................................................... 15 Primitive Region Routines ............................................................................................................... 18 Composite Regions Routines ............................................................................................................ 19 Explicit Node Pairing ..................................................................................................................... 20 Fortran Interface ............................................................................................................................ 20 Unsupported Routines Previously Available in the API .......................................................................... 24 An Example of a Customized C Program for Importing Meshes into CFX-Pre ........................................... 24 Import Programs ............................................................................................................................ 30 ANSYS ........................................................................................................................................ 31 CFX Def/Res ................................................................................................................................ 31 CFX-4 ......................................................................................................................................... 31 CFX-5.1 ....................................................................................................................................... 31 CFX-TfC ...................................................................................................................................... 32 CGNS .......................................................................................................................................... 33 ANSYS FLUENT .......................................................................................................................... 33 GridPro/az3000 ............................................................................................................................. 34 I-DEAS ........................................................................................................................................ 34 ICEM CFX ................................................................................................................................... 34 PATRAN ...................................................................................................................................... 34 NASTRAN ................................................................................................................................... 35 CFX-TASCflow ............................................................................................................................. 35 3. Mesh and Results Export API ........................................................................................................................ 37 Creating a Customized Export Program .............................................................................................. 37 An Example of an Export Program .................................................................................................... 37 Example of Output Produced ............................................................................................................ 47 Source Code for getargs.c ................................................................................................................ 48 Compiling Code with the Mesh and Results Export API ........................................................................ 50 Compiler Flags .............................................................................................................................. 50 Linking Code with the Mesh and Results Export API ............................................................................ 50 UNIX .......................................................................................................................................... 51 Windows (32-bit) ........................................................................................................................... 51 Windows (64-bit) ........................................................................................................................... 51 Details of the Mesh Export API ........................................................................................................ 51 Defined Constants and Structures ...................................................................................................... 51 Initialization and Error Routines ....................................................................................................... 53 Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. iii ANSYS CFX Reference Guide Zone Routines ............................................................................................................................... 54 Node Routines ............................................................................................................................... 55 Element Routines ........................................................................................................................... 56 Region Routines ............................................................................................................................ 57 Face Routines ................................................................................................................................ 59 Volume Routines ............................................................................................................................ 60 Boundary Condition Routines .......................................................................................................... 61 Variable Routines ........................................................................................................................... 62 4. Remeshing Guide ....................................................................................................................................... 65 User Defined Remeshing ................................................................................................................. 66 Remeshing with Key-Frame Meshes .................................................................................................. 66 Remeshing with Automatic Geometry Extraction ................................................................................. 67 ICEM CFD Replay Remeshing ......................................................................................................... 67 Steps to Set Up a Simulation Using ICEM CFD Replay Remeshing ......................................................... 69 Directory Structure and Files Used During Remeshing .......................................................................... 70 Additional Considerations ............................................................................................................... 70 Mesh Re-Initialization During Remeshing .......................................................................................... 70 Software License Handling .............................................................................................................. 71 5. Reference Guide for Mesh Deformation and Fluid-Structure Interaction ................................................................ 73 Mesh Deformation ......................................................................................................................... 73 Mesh Folding: Negative Sector and Element Volumes ........................................................................... 73 Applying Large Displacements Gradually ........................................................................................... 73 Consistency of Mesh Motion Specifications ........................................................................................ 73 Solving the Mesh Displacement Equations and Updating Mesh Coordinates .............................................. 74 Mesh Displacement vs. Total Mesh Displacement ................................................................................ 74 Simulation Restart Behavior ............................................................................................................. 74 Fluid Structure Interaction ............................................................................................................... 74 Unidirectional (One-Way) FSI .......................................................................................................... 75 Bidirectional (Two-Way) FSI ........................................................................................................... 76 6. CFX Best Practices Guide for Numerical Accuracy ........................................................................................... 81 An Approach to Error Identification, Estimation and Validation .............................................................. 81 Definition of Errors in CFD Simulations ............................................................................................. 82 Numerical Errors ........................................................................................................................... 82 Modeling Errors ............................................................................................................................ 87 User Errors ................................................................................................................................... 88 Application Uncertainties ................................................................................................................ 88 Software Errors ............................................................................................................................. 88 General Best Practice Guidelines ...................................................................................................... 89 Avoiding User Errors ...................................................................................................................... 89 Geometry Generation ...................................................................................................................... 89 Grid Generation ............................................................................................................................. 89 Model Selection and Application ....................................................................................................... 90 Reduction of Application Uncertainties .............................................................................................. 94 CFD Simulation ............................................................................................................................. 94 Handling Software Errors ................................................................................................................ 96 Selection and Evaluation of Experimental Data .................................................................................... 97 Verification Experiments ................................................................................................................. 97 Validation Experiments ................................................................................................................... 97 Demonstration Experiments ............................................................................................................. 99 7. CFX Best Practices Guide for Cavitation ....................................................................................................... 101 Liquid Pumps .............................................................................................................................. 101 Pump Performance without Cavitation .............................................................................................. 101 Pump Performance with Cavitation .................................................................................................. 102 Procedure for Plotting Performance Curve ........................................................................................ 102 Setup ......................................................................................................................................... 103 Convergence Tips ......................................................................................................................... 103 Post-Processing ............................................................................................................................ 103 8. CFX Best Practices Guide for Combustion ..................................................................................................... 105 Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. iv Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. ANSYS CFX Reference Guide Gas Turbine Combustors ................................................................................................................ Setup ......................................................................................................................................... Reactions .................................................................................................................................... Convergence Tips ......................................................................................................................... Post-Processing ............................................................................................................................ Combustion Modeling in HVAC cases .............................................................................................. Setup ......................................................................................................................................... Convergence tips .......................................................................................................................... Post-processing ............................................................................................................................ 9. CFX Best Practices Guide for HVAC ............................................................................................................ HVAC Simulations ....................................................................................................................... Setting Up HVAC Simulations ........................................................................................................ Convergence Tips ......................................................................................................................... 10. CFX Best Practices Guide for Multiphase .................................................................................................... Bubble Columns .......................................................................................................................... Setup ......................................................................................................................................... Convergence Tips ......................................................................................................................... Post-Processing ............................................................................................................................ Mixing Vessels ............................................................................................................................. Setup ......................................................................................................................................... Free Surface Applications .............................................................................................................. Setup ......................................................................................................................................... Convergence Tips ......................................................................................................................... 11. CFX Best Practices Guide for Turbomachinery ............................................................................................. Gas Compressors and Turbines ....................................................................................................... Setup for Simulations of Gas Compressors and Turbines ...................................................................... Convergence Tips ......................................................................................................................... Post-Processing ............................................................................................................................ Liquid Pumps and Turbines ............................................................................................................ Setup for Simulations of Liquid Pumps and Turbines .......................................................................... Convergence Tips ......................................................................................................................... Post-Processing ............................................................................................................................ Fans and Blowers ......................................................................................................................... Setup for Simulations of Fans and Blowers ........................................................................................ Convergence Tips ......................................................................................................................... Post-Processing ............................................................................................................................ Frame Change Models .................................................................................................................. Frozen Rotor ............................................................................................................................... Stage ......................................................................................................................................... Transient Rotor-Stator ................................................................................................................... Domain Interface Setup ................................................................................................................. General Considerations ................................................................................................................. Case 1: Impeller/Volute ................................................................................................................. Case 2: Step Change Between Rotor and Stator .................................................................................. Case 3: Blade Passage at or Close to the Edge of a Domain .................................................................. Case 4: Impeller Leakage ............................................................................................................... Case 5: Domain Interface Near Zone of Reversed Flow ....................................................................... 12. CFX Command Language (CCL) ............................................................................................................... CFX Command Language (CCL) Syntax .......................................................................................... Basic Terminology ....................................................................................................................... The Data Hierarchy ...................................................................................................................... Simple Syntax Details ................................................................................................................... 13. CFX Expression Language (CEL) .............................................................................................................. CEL Fundamentals ....................................................................................................................... Values and Expressions ................................................................................................................. CFX Expression Language Statements ............................................................................................. CEL Operators, Constants, and Expressions ...................................................................................... CEL Operators ............................................................................................................................. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. v 105 105 106 106 106 107 107 107 107 109 109 109 111 113 113 113 113 113 114 114 114 114 115 117 117 117 117 118 118 119 119 119 119 119 119 120 120 120 121 121 121 121 121 122 122 123 124 127 127 127 128 128 133 133 133 134 135 135 ANSYS CFX Reference Guide Conditional if Statement ................................................................................................................ 136 CEL Constants ............................................................................................................................. 137 Using Expressions ........................................................................................................................ 137 CEL Examples ............................................................................................................................. 138 Example: Reynolds Number Dependent Viscosity ............................................................................... 138 Example: Feedback to Control Inlet Temperature ............................................................................... 139 Examples: Using Expressions in ANSYS CFD-Post ............................................................................ 140 CEL Technical Details ................................................................................................................... 140 14. Functions in ANSYS CFX ........................................................................................................................ 141 CEL Mathematical Functions ......................................................................................................... 141 Quantitative CEL Functions in ANSYS CFX ..................................................................................... 143 Functions Involving Coordinates ..................................................................................................... 145 CEL Functions with Multiphase Flow .............................................................................................. 145 Quantitative Function List .............................................................................................................. 146 area ........................................................................................................................................... 150 areaAve ...................................................................................................................................... 151 areaInt ........................................................................................................................................ 151 ave ............................................................................................................................................ 152 count ......................................................................................................................................... 153 countTrue ................................................................................................................................... 153 force .......................................................................................................................................... 154 forceNorm .................................................................................................................................. 155 inside ......................................................................................................................................... 155 length ......................................................................................................................................... 156 lengthAve ................................................................................................................................... 156 lengthInt ..................................................................................................................................... 157 mass .......................................................................................................................................... 157 massAve ..................................................................................................................................... 157 massFlow ................................................................................................................................... 157 massFlowAve .............................................................................................................................. 158 massFlowAveAbs ......................................................................................................................... 159 Advanced Mass Flow Considerations ............................................................................................... 159 Mass Flow Technical Note ............................................................................................................. 159 massFlowInt ................................................................................................................................ 160 massInt ...................................................................................................................................... 161 maxVal ....................................................................................................................................... 161 minVal ....................................................................................................................................... 161 probe ......................................................................................................................................... 162 rmsAve ....................................................................................................................................... 162 sum ........................................................................................................................................... 162 torque ........................................................................................................................................ 163 volume ....................................................................................................................................... 163 volumeAve .................................................................................................................................. 163 volumeInt ................................................................................................................................... 164 15. Variables in ANSYS CFX ......................................................................................................................... 165 Hybrid and Conservative Variable Values .......................................................................................... 165 Solid-Fluid Interface Variable Values ................................................................................................ 166 List of Field Variables ................................................................................................................... 166 Common Variables Relevant for Most CFD Calculations ...................................................................... 167 Variables Relevant for Turbulent Flows ............................................................................................. 169 Variables Relevant for Buoyant Flow ............................................................................................... 171 Variables Relevant for Compressible Flow ........................................................................................ 171 Variables Relevant for Particle Tracking ............................................................................................ 172 Variables Relevant for Calculations with a Rotating Frame of Reference ................................................. 172 Variables Relevant for Parallel Calculations ....................................................................................... 173 Variables Relevant for Multicomponent Calculations ........................................................................... 173 Variables Relevant for Multiphase Calculations .................................................................................. 173 Variables Relevant for Radiation Calculations .................................................................................... 174 Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. vi Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. ............................................................................................................................................................................................................................................................ 261 Example 4: Creating a Complex Quantitative Subroutine ........ 224 Variables R .......................................... 217 Variables J-Q ................................... All rights reserved................................................................................................................................................................................................................................................................................................................................... 175 Particle Variables Generated by the Solver ................................. 256 Turbo Post CCL Command Actions ................... 259 Example 1: Print the Value of the Pressure Drop Through a Pipe ..................................................... 277 References 41-60 ........................................................................................1 ..................................................................................................................... 293 References 181-200 .. 184 Droplet Breakup Variable ................................................................................. Line Interface Mode ...................................................... 299 Release 12...................... 290 References 161-180 ....................................................................................................................................................................................................... 234 Variables T-Z ................................................................................................................................ 263 Power Syntax Usage ........................................ 230 Variables S ................................................................................ vii .................................................................................... 212 Variables A-C ....................................................................................... Temperatures................................................................... 260 Example 3: Creating a Simple Subroutine ...................... Bibliography ......................... 184 Particle Track Variables ........................................................................© 2009 ANSYS...................................... 273 Features Available in Line Interface Mode .............................................................................. 186 Miscellaneous Variables ..................... Command Actions ..................................................................................................................................... 250 Reading Session Files ................................................... 284 References 101-120 . 279 References 61-80 ............................................................................. Inc.................................... 288 References 141-160 ...................................................................................................................................................................... Power Syntax in ANSYS CFX ......................................... 275 References 1-20 ...... 254 Importing External File Formats ........................................................................................................................................................................................................................................................... 256 Other Commands ................................................................. 252 Creating a Hardcopy .................................... 257 18............................ 249 File Operations from the Command Editor Dialog Box ................ and Pressures ................ 191 16............................................................................................................. 260 Example 2: Using a for Loop ............................................ 259 Examples of Power Syntax ........ 239 17....................................................................................................................................................................................... 250 Loading a Results File .............. 212 Variables D-I ....... 256 Deleting Objects ................ Contains proprietary and confidential information of ANSYS.......................................................................................................................................................................................................................................... Inc................................................................. 255 Quantitative Calculations in the Command Editor Dialog Box ..................................................................................................................................................... 263 19................................................ 263 Power Syntax Subroutines .......................................................................................................................... 175 Variables and Predefined Expressions Available in CEL Expressions ....................................... 255 Controlling the Viewer ............................. 250 Saving State Files ................................................................................................................................................................................... ANSYS FLUENT Field Variables Listed by Category ......................................... 186 Multi-component Particle Variable .. 199 Alphabetical Listing of ANSYS FLUENT Field Variables and Their Definitions ......................................................................ANSYS CFX Reference Guide Variables for Total Enthalpies..................................... 273 20............................................................................................................................................................................................ 295 Glossary ...................................................................... 262 Power Syntax Subroutine Descriptions .......................... 186 Particle Field Variables ......................... 282 References 81-100 .................................................................................................................................................................................................................. 261 Predefined Power Syntax Subroutines ................................................................................................... 275 References 21-40 ............................................ and its subsidiaries and affiliates................................................................................................................................................................................................................................................................................................................................ 256 Viewing a Chart ............................................................................................................................................................ 249 Overview of Command Actions ............................................................................................................................................................................................... 254 Exporting Data ....................................... 286 References 121-140 ................................................................................................... 251 Reading State Files ................................................................................................................................................................................................................................. and its subsidiaries and affiliates.Release 12.© 2009 ANSYS. All rights reserved.1 . . Contains proprietary and confidential information of ANSYS. Inc. Inc. .................. Sequence of Synchronization Points ........ 78 7................ 122 11................ 101 7..............© 2009 ANSYS.... CFX Launcher .................. Radial Compressor ..........1.2............................................ 68 5......................................2.................................................................................................... and its subsidiaries and affiliates............................................................................................7... 122 11......................................................... Flow Rate vs Pressure Rise for a Gas Compressor ........... Flow Leakage Through Gap Near Impeller Inlet ......................1.........1....................................... r and theta with Respect to the Reference Coordinate Frame .......... 125 13............................. Element Aspect Ratio at Domain Interface .......................... Backflow ...... 66 4............... 121 11....................................................... 118 11.................. Integration of remeshing loop into general simulation workflow .................................................................................................... 139 14..........................6...............2........1.. Contains proprietary and confidential information of ANSYS............................List of Figures 1....1....................................... 160 15........................... Temperature Feedback Loop ...........4..........................1............ 65 4.... 102 10................................................................................ Inc.. Possible Domain Interface Positions with Step Change in Passage Height ............. Inc........................ All rights reserved....................................5....................... ix ....................... 124 11......................3......................... 123 11..... Cavitation Performance at Constant RPM and Flow Rate ........ 115 11............1.................. Impeller/Volute ................................. 1 4......... Domain Interface Between Blade Rows in an Axial Machine .....3......................................... Flow Rate vs Pressure Rise for a Liquid Pump ................................................. Schematic for User Defined remeshing ............... .................................................................... An exaggerated view of three inflation layers on each side of the uppermost subdomain boundary surface......................................................................1 ....................................................................... Schematic for ICEM CFD Replay remeshing ...............................................1.................................................. 182 Release 12..1........ All rights reserved. Inc. Inc.© 2009 ANSYS. Contains proprietary and confidential information of ANSYS.1 .Release 12. and its subsidiaries and affiliates. . .......2................................. 204 16..............................3................ 177 16................................................... 142 14. Cell Info...............................................10........... 211 16......................... Common CEL Field Variables and Predefined Expressions .............................................................. 202 16................................... 212 Release 12. Common CEL Single-Value Variables and Predefined Expressions ............................... CEL Multiphase Examples .................... and User Defined Memory Categories ........ and Granular Temperature Categories ............. Phases............................... xi ...................... 146 14........ 205 16...........................................................13........ CEL Functions in CFX-Pre/CFX-Solver and in CFD-Post ....................... Inc....... Discrete Phase Model........................................................... Grid........................................................... 206 16..... Radiation...................... 147 15...........................2..List of Tables 13.. 201 16..............................................© 2009 ANSYS................... Granular Pressure.... 209 16..5.......... 137 14.............. 207 16........................................ Standard Mathematical CEL Functions ....... 210 16.. Contains proprietary and confidential information of ANSYS...................... CEL Operators ..................... 200 16........................ Examples of the Calling Syntax for an Expression ........... and Solidification/Melting Categories ...... CEL Constants ...................1........................................... Wall Fluxes...... and Premixed Combustion Categories ....................................... 203 16........... Pressure and Density Categories ................2................................................... and its subsidiaries and affiliates.......1 ............... Soot.........1.... 176 15............ Inc.......................... 145 14................ Reactions............................. Species.. 208 16................................................................................7.... Turbulence Category ......................................................................12......... NOx....2.....................8..4...................... Residuals Category ......3..................... User Defined Scalars.................. Pdf........ Grid Category (Turbomachinery-Specific Variables) and Adaption Category ...........1...........................................11..................................................................... Temperature.............. Acoustics Category .............4....... and Adaption Categories ............... and Unsteady Statistics Categories ...................9.............................................................................. 136 13.............. Derivatives Category ...................................6... All rights reserved...................................... Velocity Category ..................................................................................................................................1.... Properties.................................. Inc. All rights reserved.1 .© 2009 ANSYS. .Release 12. and its subsidiaries and affiliates. Inc. Contains proprietary and confidential information of ANSYS. 1) Customizing the Launcher (p. On Windows platforms. Edit Menu Clears the text output window.© 2009 ANSYS. finds text in the text output window and sets options for the launcher.1 . a working directory selector.1. Save As Saves the contents of the output window to a file. 1 . Contains proprietary and confidential information of ANSYS. Menu Bar The CFX Launcher menus provide the following capabilities: File Menu Saves the contents of the text output window and to close the launcher. All rights reserved. Quit Shuts down the launcher. Any programs already launched will continue to run. and an output window where messages are displayed. 4) The Launcher Interface The layout of the CFX Launcher is shown below: Figure 1. Find Displays a dialog box where you can search the text in the output window. CFX Launcher This chapter describes the CFX Launcher in detail: • • The Launcher Interface (p.Chapter 1. Inc. Inc. Clear Clears the output window. an icon to start Windows Explorer in the working directory appears next to the directory selector. Release 12. a tool bar for launching applications. CFX Launcher The CFX Launcher consists of a menu bar. and its subsidiaries and affiliates. SGI. click Apply to test. Clicking either of these buttons opens the Select Font dialog box. see Customizing the Launcher (p. if they are installed. and. Show Menu Allows you to show system. The button to the right of Text Window Font applies only to the text output window.© 2009 ANSYS. Tools Menu Allows you to access license-management tools and a command line for running other CFX utilities. If an application is not found. GUI Style You can choose any one of several GUI styles. and CDE (Solaris) styles. Show All Displays all of the available information. CFX-Solver Manager Runs CFX-Solver Manager. All rights reserved. 2 Contains proprietary and confidential information of ANSYS. 3). Release 12. Inc. including information about your system. Motif. CFX Menu Enables you to launch CFX-Pre. in the current working directory as specified in Working Directory Selector (p. with the working directory as specified in Working Directory Selector (p. 3). for details. 4). with the working directory as specified in Working Directory Selector (p. installation and other information. and its subsidiaries and affiliates. Inc. choosing Windows will change the look and feel of the GUI to resemble that of a Windows application. Application Font and Text Window Font The button to the right of Application Font sets the font used anywhere outside the text output window. Once you have selected a style. each style is available on all platforms. CFX-Pre Runs CFX-Pre. installation and variables. which allows you to change the appearance of the launcher. Show Variables Displays the values of all the environment variables that are used in CFX. You can select from Windows. Show System Displays information about the CFX installation and the system on which it is being run. Platinum.Menu Bar Options Presents the Options dialog box. Show Patches Displays the output from the command cfx5info -patches. This provides information on patches that have been installed after the initial installation of CFX. . ANSYS TurboGrid) and provides a menu entry to launch the application. For example.1 . 3). CFD-Post Runs CFD-Post. CFD-Post. you can add it. other CFX products (such as ANSYS TurboGrid). Other CFX Applications The launcher also searches for other CFX applications (for example. Show Installation Displays information about the version of CFX that you are running. CFX-Solver Manager. you may be able to get a more detailed error message by starting the component from the command line than you would get if you started the component from the launcher. and its subsidiaries and affiliates. for details. Pressing any of the buttons will start up the component in the specified working directory. Edit Site-wide Configuration File Opens the site-wide configuration file in a text editor. user guides. then you will have to either type the full path of the executable in each command. any error messages produced are written to the command line window. and reference manuals online.Tool Bar ANSYS License Manager If ANSYS License Manager is installed. If you do not use the Tools > Command Line command to open a command window. a menu entry to launch it appears in the Tools menu.1 . All rights reserved. you can do any of the following: • • Type the directory name into the box and press Enter.ccl. If you are having problems with a component. Contains proprietary and confidential information of ANSYS. Inc. You may want to start components of CFX from the command line rather than by clicking the appropriate button on the launcher for the following reasons: • • • CFX contains some utilities (for example. 3 . This displays a list of recently used directories. a parameter editor) that can be run only from the command line. Which text editor is called is controlled by the settings in <CFXROOT>/etc/launcher/shared. CFX-Solver Manager and CFD-Post.© 2009 ANSYS. Command Line Starts a command window from which you can run any of the CFX commands via the command line interface. Edit File Opens a browser to edit the text file of your choice in a platform-native text editor. The command line will be set up to run the correct version of CFX and the commands will be run in the current working directory. Click on the down-arrow icon ( ) next to the directory name. for example CFX-Pre. Help Menu The Help menu enables you to view tutorials. or create new menus. Working Directory Selector While running CFX. You may want to specify certain command line arguments when starting up a component so that it starts up in a particular configuration. For related information. Which text editor is called is controlled by the settings in <CFXROOT>/etc/launcher/CFX5. see Accessing Help (p. Release 12. see Customizing the Launcher (p. 75). User Menu The User menu is provided as an example. or explicitly set your operating system path to include the <CFXROOT>/bin directory. The equivalent menu entries for launching the components also show a keyboard shortcut that can be used to launch the component. If you start a component from the command line. all the files that are created will be stored in the working directory.ccl. Configure User Startup Files (UNIX only) Information about creating startup files can be found in the installation documentation. Tool Bar The toolbar contains shortcuts to the main components of CFX. Inc. You can add your own applications to this menu. 4). To change the working directory. CCL Structure The configuration files contain CCL objects that control the appearance and behavior of menus and buttons that appear in the launcher.1 . Some parts of the launcher are not editable (such as the File. Referring to Figure 1. but others parts allow you to edit existing actions and create new ones (for example. Nothing will appear in the menu or toolbar until you add APPLICATION or DIVIDER objects to the group. 4 Contains proprietary and confidential information of ANSYS. launching your own application from the User menu). applications in one file can refer to groups in other files. The configuration files are located in the <CFXROOT>/etc/launcher/ directory (where <CFXROOT> is the path to your installation of CFX).Output Window • Click Browse to browse to the directory that you want. and its subsidiaries and affiliates. Each new GROUP creates a new menu and toolbar. There are three types of CCL objects: GROUP. Save As: Saves the output to a file. but you should not edit any of the configuration files provided by CFX. Groups with a higher Position value. The File and Edit menus are always the first two menus and the Help menu is always the last menu. An example of how to add a menu item for the Windows calculator to the launcher is given in Example: Adding the Windows Calculator (p. Edit and Help menus). 7). APPLICATION and DIVIDER objects.ccl configuration file. • Release 12. The value should be an integer between 1 and 1000. This is the name that APPLICATION and DIVIDER objects will refer to when you want to add them to this group.1. Copy Selection: Copies the selected text. 1). relative to other groups. All rights reserved. You can open these files in any text editor. “CFX Launcher” (p. Output Window The output window is used to display information from commands in the Show menu. You can right-click in the output window to show a shortcut menu with the following options: • • • • • Find: Displays a dialog box where you can enter text to search for in the output. CFX has a lower position value than the ANSYS group. other than the User. Clear: Clears the output window. will have their menu appear further to the right in the menu bar.© 2009 ANSYS. This name should be different to all other GROUP objects. it is “CFX”. The fact that there are multiple configuration files is not important. Inc. Position refers to the position of the menu relative to others. . In this case. Select All: Selects all the text. Customizing the Launcher Many parts of the launcher are driven by CCL commands contained in configuration files. The following sections outline the steps required to configure the launcher. An example of a GROUP object is given below: GROUP: CFX Position = 200 Menu Name = &CFX Show In Toolbar = Yes Show In Menu = Yes Enabled = Yes END • The group name is set after the colon. GROUP GROUP objects represent menus and toolbar groups in the launcher. Inc. exe Arguments = /c start Show In Toolbar = No Show In Menu = Yes Enabled = Yes OS List = winnt END APPLICATION: CFXSM Position = 300 Group = CFX Tool Tip = Launches ANSYS CFX-Solver Manager Menu Item Name = CFX-&Solver Manager Command = cfx5solve Show In Toolbar = Yes Show In Menu = Yes Enabled = Yes Toolbar Name = ANSYS CFX-Solver Manager Icon = LaunchSolveIcon. 5 . the object assumes a high position value (so it will appear at the bottom of a menu or at the right of a group of buttons). The value must correspond to the name that appears after “GROUP:” in an existing GROUP object. The value should be an integer between 1 and 1000. the Tool Tip entry is not used since a toolbar button is not created.xpm Shortcut = CTRL+S END • • The application name is set after the colon. Contains proprietary and confidential information of ANSYS. This parameter is optional. If you do not specify a position. For example.1 . Position: sets the relative position of the menu entry. The optional ampersand is placed before the letter that you wish to act as a menu accelerator (for example. The menu and/or toolbar entry will not be created if you do not specify a valid group name. APPLICATION: Command Line 1 Position = 300 Group = Tools Tool Tip = Start a window in which CFX commands can be run Menu Item Name = Command Line Command = <windir>\system32\cmd. • • APPLICATION APPLICATION objects create entries in the menus and toolbars that will launch an application or run a process. Menu Item Name: sets the name of the entry that will appear in the menu. Tool Tip: displays a message when the mouse pointer is held over a toolbar button. you may want to create a menu item but not an associated toolbar icon. Alt+C displays the CFX menu). This name should be different to all other APPLICATION objects. and its subsidiaries and affiliates.© 2009 ANSYS. Inc. Inc. The creation of the menu or toolbar can be toggled by setting the Show in Menu and Show in Toolbar options to Yes or No respectively. relative to other applications that have the same group. The second example creates a menu entry and toolbar button to start CFX-Solver Manager. In the ‘Command Line 1' example above. Set the option to No to grey it out. Enabled sets whether the menu/toolbar is available for selection or is greyed out. The higher the value. If you do not specify a name. Group: sets the GROUP object to which this application belongs. The optional ampersand is placed before the letter that • • • Release 12. All rights reserved.CCL Structure • The title of the menu is set under Menu Name (this menu has the title CFX). The first example creates a menu entry in the Tools menu that opens a command line window. Two examples are given below with an explanation for each parameter. The GROUP object does not have to be in the same configuration file. You must be careful not to use an existing menu accelerator. the further down the menu or the further to the right in a toolbar the entry will appear. in the first example it is “Command Line 1”. the name is set to the name of the APPLICATION: object. (HP). This parameter is optional. a relative path from <CFXROOT>/bin/ is assumed. <windir> is used in the Command parameter so that the command would work on different versions of Windows. If an absolute path is not specified. the menu item/toolbar button will not appear in the launcher. solaris (Sun). If an absolute path is not specified. and its subsidiaries and affiliates. You can specify an environment variable value in any parameter by including its name between the < > symbols. The path can be absolute (that is. Shortcut: specifies the keyboard shortcut that can be pressed to launch the application. or a drive letter on Windows). OS List can contain the following values: winnt (Windows. linux-ia64 (64-bit Linux). Icon: specifies the icon to use on the toolbar button and in the menu item. 6). You do not need to include this parameter as there are no arguments to pass. xpm) and Bitmaps (bmp). use a forward slash to begin the path on UNIX. see Including Environment Variables (p. Release 12. use a forward slash to begin the path on UNIX. The following file formats are supported for icon image files: Portable Network Graphics (png). a relative path from <CFXROOT>/etc/icons is assumed. or a drive letter on Windows). a Windows file path) you should include that argument in double quotes. The Command and Argument parameters are the only parameters that are likely to benefit from using environment variables. Inc. • • Including Environment Variables In can be useful to use environment variables in the values for some parameters. the application only applies to Windows platforms. 6 Contains proprietary and confidential information of ANSYS. For example. Set this parameter to No to grey out the application. including Windows XP). aix (IBM). Other icons used in the launcher are 32 pixels wide and 30 pixels high. You must be careful not to use an existing menu accelerator. the command to open a command line window varies depending on the operating system. Pixel Maps (ppm. In the ‘Command Line 1' example above. To complete the OS coverage. Show In Menu: determines if a menu entry is created for the application. <windir> is replaced with the value held by the windir environment variable. If OS List is not supplied. All rights reserved. the menu item/toolbar button will not appear in the CFX Launcher. for details. Inc. Arguments: specifies any arguments that need to be passed to the application. an icon will not appear. for details. The arguments are appended to the value you entered for Command. linux. see Including Environment Variables (p.© 2009 ANSYS. This optional parameter has a default value of Yes. hpux-ia64 (64-bit HP). OS List is an optional parameter that allows you to set which operating system the application is suitable for. the launcher will attempt to create the menu item and toolbar button on all platforms. In the ‘Command Line 1' example above. An example of the CCL for DIVIDER objects is shown below. This parameter is optional (since you may only want to show an icon).1 . The path and command are checked when the CFX Launcher is started. alt+c then s will start CFX-Solver Manager. for example: Arguments = “C:\Documents and Settings\User” arg2 arg3 • • • • Show In Toolbar: determines if a toolbar button is created for the application. The path can be absolute (that is. the launcher configuration files contain more ‘Command Line' applications that apply to different operating systems. You may find it useful to include environment variables in a command path. • Command: contains the command to run the application. hpux. If it is not included. • • Toolbar Name: sets the name that appears on the toolbar button. Enabled: allows you to grey out the menu entry and toolbar button. If you need to pass an argument that contains spaces (for example. If no command is specified. You must be careful not to use a keyboard shortcut that is used by any other APPLICATION object. This optional parameter has a default value of Yes. You may find it useful to include environment variables in the arguments. DIVIDER DIVIDER objects create a divider in a menu and/or toolbar (see the Tools menu for an example). Distinct arguments are space-separated.CCL Structure you want to have act as a menu accelerator (for example. 6). . If the path or command does not exist. This optional parameter has a default value of Yes. Alt+c selects the CFX menu and “s” selects the entry from the menu). Environment variables included in the Arguments parameter are expanded before they are passed to the application. linux-ia64. All rights reserved.Example: Adding the Windows Calculator DIVIDER: Tools Divider 1 Position = 250 Group = Tools OS List = winnt. see APPLICATION (p.1 . Example: Adding the Windows Calculator The following CCL is the minimum required to add the Windows calculator to the launcher: GROUP: Windows Apps Menu Name = Windows END APPLICATION: Calc Group = Windows Apps Command = <windir>\system32\calc.exe Toolbar Name = Calc END Although the parameter Toolbar Name is not strictly required. Contains proprietary and confidential information of ANSYS. you would end up with a blank toolbar button if it were not set. solaris END The Position. Inc. Inc. linux. hpux-ia64.© 2009 ANSYS. and its subsidiaries and affiliates. 7 . aix. For details. Release 12. hpux. 5). Group and OS List parameters are the same as those used in APPLICATION objects. Inc. and its subsidiaries and affiliates. .© 2009 ANSYS.1 .Release 12. All rights reserved. Contains proprietary and confidential information of ANSYS. Inc. For details on using the Volume Mesh Import API. Contains proprietary and confidential information of ANSYS. 30) Valid Mesh Elements in CFX The CFX-Solver technology works with unstructured meshes. Inc. and its subsidiaries and affiliates. The CFX-Solver can solve flows in any mesh comprising one or more of the following element types: You must write the program using the API to translate the mesh read from the 3rd-party file into a format that can be processed by CFX-Pre. see User Import (p. This chapter describes: • • • • • Valid Mesh Elements in CFX (p. This does not prohibit the use of structured meshes. 12) An Example of a Customized C Program for Importing Meshes into CFX-Pre (p. 24) Import Programs (p. Volume Mesh Import API The Mesh Import Application Programming Interface (API) enables you to build a customized executable that reads a 3-dimensional mesh from a 3rd-party mesh file into CFX-Pre and to extend the number of file formats that CFX-Pre can understand and read beyond those supplied as part of the standard installation. Inc. 9) Creating a Custom Mesh Import Executable for CFX-Pre (p.© 2009 ANSYS. 10) Details of the Mesh Import API (p.Chapter 2.1 . The communication between the executable and CFX-Pre is via a communications channel that is controlled by use of routines in the API provided. All rights reserved. 9 . 62). However a structured mesh will always be dealt with internally as an unstructured mesh. Release 12. but use icc compiler -m64 -q64 (the linker may also need -b64) Release 12. The installation contains a C source code example file that can be used as the basis of your custom executable. Initialization for import with the cfxImportInit routine. This file.© 2009 ANSYS. A number of API functions are provided in a library supplied with the ANSYS CFX installation. After writing the program. For details. Definition of element data with cfxImportElement. If you do not use the header file cfxImport. see User Import (p. Inc. 6. Inc. For details.Creating a Custom Mesh Import Executable for CFX-Pre Creating a Custom Mesh Import Executable for CFX-Pre You can create your own customized program using the 'C' programming language or Fortran programming language. and its subsidiaries and affiliates. 2. 10 Contains proprietary and confidential information of ANSYS. see Linking Code with the Mesh Import API (p. 62). it can be run in CFX-Pre. Definition of node data with cfxImportNode. see Details of the Mesh Import API (p. . cfxImportAddReg.1 . 24). see Compiling Code with the Mesh Import API (p. Inclusion of the cfxImport. Optionally. The basic structure of a program written to import a 3rd party mesh into CFX-Pre is as follows: 1. After a customized executable has been produced. All rights reserved. you will need to compile the source code. The customized executable must also be linked with the provided mesh import API library and the provided i/o library as detailed in Linking Code with the Mesh Import API (p.0W +DA2. and is listed in: An Example of a Customized C Program for Importing Meshes into CFX-Pre (p. the functionality of the routines contained within the API may not follow defined behavior. 3. For details. cfxImportEndReg Data transfer with cfxImportDone. Note Windows users should note that custom mesh import programs must be compiled as multi-threaded applications.h header file (for C programs and not Fortran programs). 10). 4. 5. For details. 11).c.h. The header files associated with the API are located in <CFXROOT>/include/. Compiler Flags The following compiler flags are necessary for successful compilation on the listed platforms: Platform hpux (pa-2) hpux-ia64 linux (32-bit) linux-ia64 solaris aix Flag +DS2.0W +DD64 <none> <none>. definitions of 2D and 3D regions with either cfxImportRegion or the following three functions: cfxImportBegReg. Compiling Code with the Mesh Import API Compilation of a customized executable must be performed using an appropriate compiler and compiler flags. 11). is provided in <CFXROOT>/examples/. 12). ImportTemplate. You will also need to link your routine with the API routine libraries. lib.lib libratlas.a (on UNIX/Linux) bufferoverflowu. -lunits.lib libpgtapi.lib libpgtapi. while -lm and -lc are system libraries.c /link /libpath:"C:\Program Files\Ansys Inc\v121\CFX\lib\winnt" libcclapilt.lib libmeshimport. or libratlas.lib (on Windows).a (on UNIX/Linux) libpgtapi. or libratlas_api.c -I<CFXROOT>/include/ -o myimport -L<CFXROOT>/lib/<os> \ -lmeshimport -lratlas_api -lratlas -lpgtapi -lunits -lcclapilt -lio \ -lm -lc Here. and its subsidiaries and affiliates.lib libunits.lib libmeshimport. -lpgtapi.lib libio. or libcclapilt. 11 . or libpgtapi.lib (on Windows). Inc.lib libratlas. -lmeshimport.a (on UNIX/Linux) libratlas. You should ensure that the libraries to which you are linking (which are in the path given after -L) appear on the command line after the source file (or object file if you are just linking to an existing object).exe Linking a Customized Mesh Import Executable on a 32-bit Windows Platform You can build the executables on 32-bit Windows systems that have Microsoft Visual C++ 2005 Express Edition.lib libratlas_api.lib (on Windows).c and the executable file will be called myimport.a (on UNIX/Linux) libunits. these libraries are located in <CFXROOT>/lib/<os>/: • • • • • • • • libmeshimport.F -L<install_dir>/lib/linux -lmeshimport -lratlas_api -lratlas \ -lpgtapi -lunits -lcclapilt -lio -o myImport.c /link /libpath:”C:\Program Files\Ansys Inc\v121\CFX\lib\winnt-amd64” libcclapilt. Inc. An example command line follows: cl /MD /I “C:\Program Files\Ansys Inc\v121\CFX\include” ImportTemplate.© 2009 ANSYS. -lratlas_api. or libmeshimport.lib (on Windows).lib (on Windows 64-bit) Linking a Customized C Mesh Import Executable on a UNIX Platform On most UNIX systems you should be able to build the executable with the command: cc myimport. your own import program is named myimport. In this example. or libunits. With the exception of bufferoverflowu. -lcclapillt.lib libunits.a (on UNIX/Linux) libio. when the source code for the executable is written in Fortran: g77 myImport.a (on UNIX/Linux) libcclapilt. or libio. An example command line follows: cl /MD /I "C:\Program Files\Ansys Inc\v121\CFX\include" ImportTemplate. and -lio indicate the libraries mentioned above.1 . Contains proprietary and confidential information of ANSYS.lib libio.lib libratlas_api.lib Linking a Customized Mesh Import Executable on a 64-bit Windows Platform You can build the executables on 64-bit Windows systems that have Windows Server 2003 Platform SDK.lib (on Windows). Linking a Customized Fortran Mesh Import Executable on a UNIX Platform The following is an example of how to build the executable on Linux.lib (on Windows). it must be linked with several libraries.lib bufferoverflowu. All rights reserved.a (on UNIX/Linux) libratlas_api. -lratlas.Linking Code with the Mesh Import API Linking Code with the Mesh Import API In order to build a customized import utility routine.lib Release 12.lib (on Windows). which are identified by the number of nodes: Tetrahedrons (4 nodes). pyramids (5 nodes). Region Types Regions may be defined in terms of nodes. 14) Node Routines (p. Release 12. 20) Fortran Interface (p. This allows a greater number of nodes and elements to be imported than in the past. 20) Unsupported Routines Previously Available in the API (p. 18) Composite Regions Routines (p.1 . 15) Primitive Region Routines (p. 19) Explicit Node Pairing (p. Defined Constants The following are defined in the header file cfxImport. This section contains details of: • • • • • • • • • • • Defined Constants (p. which should be included in the import program. 24) Note In past releases of ANSYS CFX the API has defined IDs of nodes and elements as integers (int). 10). Inc. 13) Termination Routines (p. All rights reserved. it is highly recommended that you read Creating a Custom Mesh Import Executable for CFX-Pre (p. based on the type argument to the cfxImportBegReg or cfxImportRegion routines. Inc. and its subsidiaries and affiliates.Details of the Mesh Import API Details of the Mesh Import API This section contains information about the functions that are used to write a customized import executable in the Mesh Import API. Before trying to use any of the routines listed in this section. 12 Contains proprietary and confidential information of ANSYS. This release now uses a datatype ID_t to represent these quantities.h. The element types may be identified by the defined constants: #define #define #define #define cfxELEM_TET cfxELEM_PYR cfxELEM_WDG cfxELEM_HEX 4 5 6 8 The element node ordering and local face numbering follow Patran Neutral file conventions for element descriptions. Element regions define 3D regions of the imported mesh. 13) Error Handling Routines (p. faces or elements. . The three types are defined by the defined constants: #define cfxImpREG_NODES #define cfxImpREG_FACES #define cfxImpREG_ELEMS 1 2 3 Node and Face regions define 2D regions of the imported mesh. and hexahedrons (8 nodes). Element Types There are currently 4 types of elements. 12) Initialization Routines (p. This type is currently defined as an unsigned integer (unsigned int). wedges or prisms (6 nodes). 15) Element Routines (p.© 2009 ANSYS. In this case it is advisable to use Face regions. If not called within 60 seconds.1 . If called and there is no connection with CFX. Inc. This routine should be called early on in the import program to let CFX know that data is to be sent. Release 12. or cfxImportTest for testing the import routine in stand-alone mode. Contains proprietary and confidential information of ANSYS. cfxImportTest int cfxImportTest (filename) char *filename. cfxImportInit void cfxImportInit () Performs initialization to begin communicating with CFX. and then transfers the data to CFX.Initialization Routines It is best to use face regions to define 2D regions of the mesh and element regions to define 3D regions of the mesh. then the routine cfxImportTest("/dev/null") (UNIX) or cfxImportTest("null") (Windows) will be called. CFX will terminate the import process. Inc. cfxImportStatus int cfxImportStatus () Returns 0 if descriptor is not opened and -1 if not opened for writing. Note Due to the limited topological information recoverable from a set of nodes it is not advisable to define 2D regions internal to a 3D region using nodes. cfxImportFatal will be called. All rights reserved. This transformation requires the node IDs specified to define vertices of valid element faces. Node regions are specified by a list of node ID's. Face regions are defined by a list of face IDs. This routine allows testing of import program in isolation from CFX by writing data to a file filename instead of attempting to write it to the CFX communication channel. This routine will be automatically called by most of the API routines if not already called. There is no return value for this routine. and 2 if opened for writing to a file. This function performs the final processing of the import data. In the case of an error. The routine will return the file descriptor of the output file or will terminate with a call to cfxImportFatal on error. In the normal case. With the exception of cfxImportStatus the first call to the Import API must be either cfxImportInit for communication with CFX. and its subsidiaries and affiliates. Node regions will be automatically transformed into a face region by the import process. 1 is returned if opened for writing to CFX.© 2009 ANSYS. If no element faces can be constructed from the defined node region the node region will be deleted. These face IDs are a combination of an element ID and a local face number in the element. Termination Routines With the exception of cfxImportTotals the last call to the Import API must always be cfxImportDone. 13 . Initialization Routines The following routines check and initialize the Import API. © 2009 ANSYS. errmsg. callback is the application-supplied function to be called in the case of an error. Returns the total number of bytes transferred to CFX by the import program. which is: counts[cfxImpCNT_NODE] counts[cfxImpCNT_ELEMENT] counts[cfxImpCNT_REGION] counts[cfxImpCNT_UNUSED] counts[cfxImpCNT_DUP] counts[cfxImpCNT_TET] counts[cfxImpCNT_PYR] counts[cfxImpCNT_WDG] counts[cfxImpCNT_HEX] = = = = = = = = = number number number number number number number number number of of of of of of of of of nodes elements regions unused nodes duplicate nodes tetrahedral elements pyramid elements wedge elements hexahedral elements The return value for the function is the total number of bytes of data sent to CFX or written to the test file given when cfxImportTest was called. Inc. which will be passed by cfxImportFatal and should be processed by the callback function as a brief message describing the error that has occurred. Get the total number of nodes. The values returned in counts may be indexed by the enum list in cfxImport. Inc.1 . cfxImportTotals long cfxImportTotals (counts) size_t counts[cfxImpCNT_SIZE].Error Handling Routines cfxImportDone long cfxImportDone () Indicate to the import API that all mesh data has been given and the API should now send the data to CFX. shutting down the program and communication with ANSYS CFX. 14 Contains proprietary and confidential information of ANSYS.h. shut down the communication channel or test file and call the user callback function (if specified by a call to cfxImportError). This routine will send the message to CFX. Error Handling Routines The first error handling routine allows the programmer to define an error callback function that is called when a fatal error is generated by the API or explicitly by the programmers code. The second routine performs a method for clean termination of the program. Define a user routine to be called before terminating due to a fatal error. cfxImportError void cfxImportError (callback) void (*callback)(char *errmsg). If this function is not called or callback is not specified. Except for cfxImportTotals. The callback routine takes a single argument. regions and other useful information given to the mesh import API by the program. . cfxImportFatal void cfxImportFatal (errmsg) char *errmsg. which should be of size at least cfxImpCNT_SIZE (currently defined as 9). Release 12. errmsg. elements. this should be last call made to the API. This information is returned in the array counts. then the normal termination behavior of the mesh import API will be that the any fatal errors will write the error message to stderr as well as being sent to CFX. and its subsidiaries and affiliates. Terminate with an error message. All rights reserved. © 2009 ANSYS. int elemtype. and z.h for convenience: #define cfxELEM_TET #define cfxELEM_PYR 4 5 /* tet element (4 nodes) /* pyramid element (5 nodes) */ */ Release 12. y. z) ID_t nodeid. 15 . y. pyramids (5 vertices). The memory for the array returned is allocated using malloc by the routine. Node Routines These routines define the 3D coordinates of points in space(nodes) which will be used to define elements or 2D regions which are to be imported to CFX. y. double *x. Define a new element to be imported to CFX. Also included here are routines which get the local face number and vertices of an element. Inc. x. Returns 0 if nodeid is invalid (less than 1). Define a node in the import API to be subsequently imported into CFX. *y. cfxImportNodeList ID_t * cfxImportNodeList () Returns an array of all node identifiers currently defined or NULL if no nodes have been defined. cfxImportGetNode ID_t cfxImportGetNode (nodeid. Element Routines The following routines define the topology of elements (using node ID's) which are to be imported to CFX. elemtype is the number of vertices for the element. If a node with the same identity has already been defined. z. Returns 0 if the node has not been defined or the node ID for the node. cfxImportNode ID_t cfxImportNode (nodeid. z) ID_t nodeid. All rights reserved. and the coordinates of the node by x. If an element with the same ID has already been defined. Only volume elements are currently supported by CFX.1 . cfxImportElement ID_t cfxImportElement (elemid. y. consequently it should be destroyed when no longer required by calling free. x. The unique identifier of the node is given by nodeid. Contains proprietary and confidential information of ANSYS.Node Routines There is no return from this call. Get the coordinates for the node identified by nodeid and return the values in x. cfxImport. *nodelist. these may be tetrahedrons (4 vertices). prisms (6 vertices) or hexahedrons (8 vertices). nodelist) ID_t elemid. it will be replaced by the new element being defined. elemtype. and z. *z. Inc. and its subsidiaries and affiliates. or nodeid is successfully defined. y. the element type by elemtype and the list of vertices by nodelist. double x. The first entry in the array is the number of nodes currently defined. the coordinate values will alter to the supplied values. The import program will terminate immediately after clean up tasks have been performed. The unique identifier of the element is given by elemid. Each node has a unique identifier called a node ID. The following defines are included in the header file. Element Routines #define cfxELEM_WDG #define cfxELEM_HEX 6 8 /* wedge element (6 nodes) /* hex element (8 nodes) */ */ The list of vertices in nodelist refers to ID's of nodes which on termination of the import program by a call to cfxImportDone must have been defined by calls to cfxImportNode. Returns 0 in the case of an elemid is invalid (less than 1) or an unsupported value is given by elemtype. 56). Release 12. The vertex ordering for the elements follows Patran Neutral File element conventions. nodelist[]. . Inc. This array needs to be at least as large the number of vertices for the element (a size of 8 will handle all possible element types). or the element type (number of vertices). All rights reserved. cfxImportGetElement ID_t cfxImportGetElement (elemid. nodelist) ID_t elemid. The node ID's will be ordered in the order expected by cfxImportElement if the program was to redefine the element. For details. Get the node ID's for corresponding to the vertices of element identified by elemid and store in the array nodelist. If this is not the case a fatal error will be reported and the API will terminate.© 2009 ANSYS. or elemid if the element is successfully defined.1 . 16 Contains proprietary and confidential information of ANSYS. and is shown in the following figure. Returns 0 if the element is not defined. Note The vertex ordering for the export API is different. Inc. If the element already exists the vertices of the element will be redefined. see cfxExportElementList (p. and its subsidiaries and affiliates. © 2009 ANSYS. cfxImportGetFace ID_t cfxImportGetFace (elemid. The first entry in the array is the number of elements. consequently it should be destroyed when no longer required by calling free. 17 . The memory for the array returned is allocated using malloc by the routine. The node ID's are returned in nodelist. Inc. Inc. Contains proprietary and confidential information of ANSYS. The face numbers and associated node indices are modeled after Patran Neutral File elements. The nodes correspond to the vertices of the face and are ordered counter-clockwise such that the normal for the face points away from the element. nodelist[].1 . nodelist) ID_t elemid. and its subsidiaries and affiliates. and are tabulated here: Element Type tetrahedron Face 1 2 3 4 pyramid 1 2 3 4 5 prism 1 2 3 4 5 hexahedron 1 2 3 4 5 6 Nodes 1 1 2 1 1 1 2 3 1 1 4 1 1 2 1 3 1 2 5 1 3 2 3 4 4 2 3 4 5 3 5 2 4 3 2 4 4 3 6 5 2 4 4 3 3 5 5 5 4 2 6 5 6 6 6 8 3 7 7 8 4 3 5 5 7 2 6 8 4 2 Release 12. All rights reserved. Gets the node ID's for the local facenum'th face of the element identified by elemid.Element Routines cfxImportElementList ID_t * cfxImportElementList () Returns an array of all the currently defined element ID's or NULL if no elements have been defined. which should be of at least of size 4. int facenum. facenum. int nnodes. 59). cfxImportEndReg will be called. It is not currently possible to mix types in a region. Initialize for the specification of a region. Returns -1 if the element is not found or nodeid is not supplied or nnodes is greater than 4 or less than 3. cfxImportAddReg int cfxImportAddReg (numobjs. A region must be currently defined or reactivated by cfxImportBegReg or an error will occur. Release 12. cfxImportBegReg int cfxImportBegReg (regname. doing so will cause the import API to terminate with an error message. nodeid[]. The type of region is given by regtype. 18 Contains proprietary and confidential information of ANSYS. which should be one of cfxImpREG_NODES. faces or elements) currently in the region. cfxImpREG_FACES or cfxImpREG_ELEMS depending on whether the region is to be defined by nodes. Primitive Region Routines The following routines allow for the specification of 2D regions as a group of nodes or faces. and its subsidiaries and affiliates. or a 3D region as a group of elements. If a region is currently being defined. the name Unnamed Region 2D or Unnamed Region 3D.© 2009 ANSYS. with a sequential integer appended. Returns the total number of objects in the current region after the object ID's have been added. nnodes is the number of nodes for the face (3 or 4). regtype) char *regname. face ID's or element ID's specified in the object list must have been defined by the appropriate routine or they will be removed from the region. If the region name is NULL. Inc. Returns -1 if the element has not been defined. or element ID's. For details. All rights reserved. then additional objects will be added to the previous region. nodeid) ID_t elemid. will be used.Primitive Region Routines Note The face numbers and associated node indices are different when exporting elements. face ID's. Returns the number of objects (node. . Gets the local face number in element identified by elemid that contains all the nodes supplied by the calling routine in nodeid. Add ID's of objects being defined to the current region. or the number of nodes for the face (3 or 4): cfxImportFindFace ID_t cfxImportFindFace (elemid. *objlist. The number of objects to add is given by numobjs and the ID's of the objects are supplied in objlist. and the API will terminate. depending on the type of the region indicated when cfxImportBegReg was called. Returns 0 if there is no match. The objects are interpreted as node ID's. nnodes. In the case of nodes and faces. Inc. int regtype. see cfxExportFaceNodes (p. The name of the region is given by regname. any node ID's . faces or elements. On calling cfxImportDone. only those which are define faces of valid imported elements will be imported. respectively. objlist) int numobjs. 0 if the face number is out of range. or the local face number (1 to 6) of the element. others are ignored by CFX.1 . If a region named regname has already been defined. This routine combines calls to cfxImportBegReg. Returns the total number of objects in the region on termination of the routine. numobjs. The memory for the array is allocated using malloc by the routine.Composite Regions Routines cfxImportEndReg int cfxImportEndReg () End the specification of the current region. Import a region named regname of type regtype. Returns -1 if a primitive region regionName is already defined or memory couldn't be allocated. The memory for the array and each character string in the array returned is allocated using malloc by the routine. All rights reserved. cfxImportRegion int cfxImportRegion (regname. Begin defining a composite region with the name regionName. and the list of object ID's by objlist. regtype. or NULL if the region does not exist. faces or elements) in the region. Returns the number of objects (nodes. numobjs.1 . The first entry in the returned list is the region type and the second entry is the number of object ID's. consequently each array member and the array itself should be destroyed when no longer required by calling free. cfxImportGetRegion int * cfxImportGetRegion (regname) char *regname. objlist) char *regname. consequently the array itself should be destroyed when no longer required by calling free. Composite Regions Routines The following routines allow composite regions to be defined in terms of primitive regions or other composite regions. *objlist. cfxImportBegCompRegion cfxImportBegCompReg() char *regionName. Contains proprietary and confidential information of ANSYS. Release 12. and its subsidiaries and affiliates. cfxImportAddReg and cfxImportEndReg. The number of objects to add to the region is given by numobjs. 19 . or 0 if successfully created.© 2009 ANSYS. int regtype. Returns a list of objects in the region named regname. Inc. cfxImportRegionList char ** cfxImportRegionList () Return a NULL terminated list of currently defined region names. Inc. and interface with the corresponding C routine. For details. mapid. components) char *regionName.© 2009 ANSYS.Explicit Node Pairing cfxImportAddCompRegComponents int cfxImportAddCompRegComponents(componentCount.components) int componentCount. mapid) ID_t nodeid. **components. see Importing Meshes (p. cfxinit call cfxinit Interface to cfxImportInit. cfxImportCompositeRegion int cfxImportCompositeRegion(regionName. componentCount. Returns -1 if a composite region isn't being defined or insufficient memory is available to add the components of the composite region. Release 12. or 0 if the components were successfully added. cfxImportEndCompReg int cfxImportEndCompReg() Finish defining the current composite region. Returns 0 if successful or -1 if an error occurred preventing the composite region being defined. and its subsidiaries and affiliates. int componentCount. Add a set of component region names specified in components to the composite region currently being defined. Returns -1 if a composite region isn't currently being defined or 0 otherwise. Inc. Explicit Node Pairing The following routine provides a method for explicitly marking two nodes as being identical (or in the same position in space). cfxImportMap ID_t cfxImportMap (nodeid. All rights reserved. On calling cfxImportDone the Mesh Import API will update regions and elements referencing the mapped node to the node it is mapped to. 20 Contains proprietary and confidential information of ANSYS. Duplicate nodes may also be removed by CFX if the appropriate options are selected in the CFX interface and an appropriate tolerance set. 51) in the ANSYS CFX-Pre User's Guide. This therefore reduces the total node count imported to CFX and eliminates the duplicate nodes. There are currently no return values. Fortran Interface The following routines are callable from Fortran. Initializes for import. char **components. Inc. componentCount specified how many components are specified in the components array.1 . Explicitly map the node identified by nodeid to the node identified by mapid. Define a composite region named regionName with componentCount components supplied in character array components. . z) Interface to cfxImportGetNode.z call cfxnodg(idnode. Specify the units the mesh is specified in.x. y. Emit a warning message mesg.x. cfxunit CHARACTER*n units call cfxunit(units) Interface to cfxImportUnits. Contains proprietary and confidential information of ANSYS. Terminates the program and transfers the data to CFX-Pre. idnode is an INTEGER value for the node ID. cfxdone call cfxdone Interface to cfxImportDone.y. and z are the DOUBLE PRECISION coordinates of the node. All rights reserved. Release 12. cfxnode INTEGER idnode DOUBLE PRECISION x. Inc. Emit a warning message mesg and terminate the program cleanly.y. Imports a node with the specified coordinates. Queries the current coordinates or a node referenced by idnode. 21 . filename is a CHARACTER*n value which gives the name of the file to dump the output to.y. y. Inc.Fortran Interface cfxtest CHARACTER*n filename call cfxtest(filename) Interface to cfxImportTest.© 2009 ANSYS. and x. and its subsidiaries and affiliates. and z are the DOUBLE PRECISION coordinates of the node. and x.1 .z call cfxnode(idnode.y. cfxnodg INTEGER idnode DOUBLE PRECISION x.z) Interface to cfxImportNode. idnode is an INTEGER value for the node ID. cfxwarn CHARACTER*n mesg call cfxwarn(mesg) Interface to cfxImportWarning. cfxfatl CHARACTER*n mesg call cfxfatl(mesg) Interface to cfxImportFatal. elefc) Interface to cfxImportFindFace. Release 12.nodes) Interface to cfxImportGetElement. Both are of type INTEGER. vtx(*) INTEGER cfxface(eleid. It should be dimensioned of size at least itelem. id call cfxfacd(eleid.4. Retrieves the list of all valid node IDs having been imported into the API. nodes is an array of INTEGER node IDs dimensioned of size at least itelem. Queries the current node ids that define the vertices of the element referenced by the id idelem. and its subsidiaries and affiliates. elefc. Defines a face id (id) in terms of an element ID (eleid) and local face (elefc) of that element. elefc. or 8). Both are of type INTEGER. Inc. 6.6. idelem is element ID.itelem. cfxeles INTEGER ids(*) call cfxeles(ids) Interface to cfxImportElemList. ids is an INTEGER array that must be at least as large as the number of elements currently imported. elefc call cfxffac(eleid.Fortran Interface cfxnods INTEGER ids(*) call cfxnods(ids) Interface to cfxImportNodeList. cfxeleg INTEGER idelem. vtx) Interface to cfxImportGetFace. Retrieves the list of all valid element IDs having been imported into the API.© 2009 ANSYS. Returns the local face (elefc) of an element (eleid) which is defined by the vertices (vtx). and itelem is the element type (number of nodes . elefc. nvtx. 22 Contains proprietary and confidential information of ANSYS.itelem.nodes) Interface to cfxImportElement. Inc. nodes is an array of INTEGER values that will contain the node IDs on successful return. All rights reserved.itelem. cfxffac INTEGER eleid. vtx(*).nodes(*) call cfxeleg(idelem.1 . Returns the node IDs of the vertices defining a face located by the element ID (eleid) and local face (elefc) of that element.5. cfxface INTEGER eleid. cfxelem INTEGER idelem. id) Interface to cfxImportFaceID. nvtx. . vtx. 5. or 8).nodes(*) call cfxelem(idelem. elefc. ids is an INTEGER array that must be at least as large as the number of nodes currently imported. cfxfacd INTEGER eleid.itelem. idelem is element ID. and itelem is the element type (number of nodes 4. obj(*) call cfxregg(regname. cfxregg CHARACTER*n regname INTEGER type. and its subsidiaries and affiliates. cfxregs CHARACTER*n regname INTEGER numobj call cfxregs(regname.objs(*) call cfxrega(nobjs.objs) Interface to cfxImportRegion.type. Inc. Contains proprietary and confidential information of ANSYS. or 3 for elements. 2 for faces.Fortran Interface cfxregn CHARACTER*n regname INTEGER type.type) Interface to cfxImportBegReg. Regname is a CHARACTER*n string defining the region name. regname is a CHARACTER*n string defining the region name. All rights reserved. type is INTEGER and objs is an INTEGER array at least of the size returned by cfxregs.1 . and objs is an INTEGER array of object IDs dimensioned at least size nobjs. type is an INTEGER value specifying the type of region.objs(*) call cfxregn(regname. cfxrege call cfxrege() Interface to cfxImportEndReg. cfxrega INTEGER nobjs. nobjs is an INTEGER value which gives the number of objects to add to the region. Inc.nobjs. objs) Get the type (type) and object IDs (objs) referenced by the region regname.© 2009 ANSYS.numobj) Query how many objects (returned in numobj) are referenced by the region regname.nobjs. nobjs is an INTEGER value which gives the number of objects in the region. cfxregb CHARACTER*n regname INTEGER type call cfxregb(regname. and objs is an INTEGER array of object IDs dimensioned at least size nobjs. type. regname is a CHARACTER*n string specifying the region name.objs) Interface to cfxImportAddReg. Finish defining the current region (after the call there will be no current region). Add the objects (objs) to the current region. regname is a CHARACTER*n string specifying the region name. either 1 for nodes. 23 . Start defining a new region or make an existing region of the same name the current one if it already exists and is of the same type. Release 12. 2 for faces. type is an INTEGER value specifying the type of region. either 1 for nodes. or 3 for elements. Inc.h> #include <string. nregs is an INTEGER value which gives the number of regions to add to the region.c . /* * ImportTemplate. 2 (elements) and 21 (named groups) * and optionally packet 6 (loads).h> #include <stdlib. Add the region names (regs) to the current composite region being defined. These routines have been removed because they are directly implemented in CFX.h> #include <ctype.1 .Unsupported Routines Previously Available in the API cfxcmpb CHARACTER*n regname call cfxcmpb(regname) Interface to cfxImportBegCompReg. Finish defining the current composite region (after the call there will be no current composite region). cfxcmpe call cfxcmpe() Interface to cfxImportEndCompReg.Patran Neutral File Import * reads packets 1 (nodes).c.h> Release 12.1 certain functionality available in previous releases is no longer supported. can be found in <CFXROOT>/examples.regs) Interface to cfxImportAddCompReg.© 2009 ANSYS. and regs is a CHARACTER*(*) array of region names dimensioned at least size nregs. Unsupported Routines Previously Available in the API In ANSYS CFX 12. ImportTemplate. All rights reserved. The following is a list of routines removed from the mesh import API: cfxImportFixElements cfxImportTolerance cfxImportGetTol cfxImportSetCheck cfxImportRange cfxImportCheck cfxtol cfxset cfxchk An Example of a Customized C Program for Importing Meshes into CFX-Pre This example. Inc. regname is a CHARACTER*n string defining the region name. and its subsidiaries and affiliates. and sends data to TfC */ #include <stdio. 24 Contains proprietary and confidential information of ANSYS. cfxcmpa INTEGER nregs CHARACTER*(n) regs call cfxcmpa(nregs. . Start defining a new composite region or make an existing composite region of the same name as the current one if it already exists. #endif { fprintf (stderr. "%s on line %d\n". nodes[8]. n = 0. 25 .h> #include <sys/types. } /*---------. n++) { if ('1' == data[n]) nodes[nnodes++] = n.h" static char options[] = "vlF:". Inc. char errmsg[81].distributed loads". if (!elemtype) { sprintf (errmsg. char *data. " -l = process packet 6 .An Example of a Customized C Program for Importing Meshes into CFX-Pre #include <math. char *data) #else elemid.© 2009 ANSYS. n < 8. All rights reserved. lineno). ID_t nodeid[8]. } /* if node flags set. elemnodes). /*---------.c [options] Patran_file". Inc. use the node values */ if (nnodes) { ID_t elemnodes[8]. n++) { if (nodes[n] >= elemtype) { Release 12. "element %d not found for packet 6\n".h" #include "getargs. data) int elemid. /* check for node flags set */ for (nnodes = 0. "options:". " -v = verbose output". static void print_error ( #ifdef PROTOTYPE char *errmsg) #else errmsg) char *errmsg. NULL }. elemid).1 .h> #include "cfxImport. nnodes. and its subsidiaries and affiliates.h> #include <sys/stat. cfxImportFatal (errmsg).add_face ----------------------------------------------* add an element face to the region list *-------------------------------------------------------------------*/ static void add_face ( #ifdef PROTOTYPE int elemid. errmsg. } for (n = 0.print_error ------------------------------------------* print error message and line number *------------------------------------------------------------------*/ static int lineno = 0. int elemtype = cfxImportGetElement (elemid. Contains proprietary and confidential information of ANSYS. #endif { int n. n < nnodes. static char *usgmsg[] = { "usage : ImportTemplate. nodeid). char *p. \ lineno++. sizeof(buffer). int verbose = 0.} void main (argc. } /*========== main ===================================================*/ #define getline() \ {if (NULL == fgets (buffer. nlines. All rights reserved. Inc. { int n. fp)) \ cfxImportFatal ("premature EOF"). 26 Contains proprietary and confidential information of ANSYS. while ((n = getargs (argc. break. nnodes = cfxImportGetFace (elemid. cfxImportFatal (errmsg).1 . struct stat st. int elemid. int nnodes. NULL). "invalid face number for element %d\n". } } /* else get nodes from face number */ else { int faceid = atoi (&data[8]). "invalid node flags for element %d\n". } nodeid[n] = elemnodes[nodes[n]]. char *testfile = NULL. double xyz[3]. cfxImportFatal (errmsg). case 'F': testfile = argarg. elemid). } if (0 == nnodes) { sprintf (errmsg. } Release 12. elemid). cfxImportFatal (errmsg). argv) int argc. packet. int lastid = -1. . do_loads = 0. if (argc < 2) usage (usgmsg. loadid. break. break. "element %d not found for packet 6\n". ID_t nodeid[8].An Example of a Customized C Program for Importing Meshes into CFX-Pre sprintf (errmsg. } } cfxImportAddReg (nnodes. options)) > 0) { switch (n) { case 'v': verbose = 7. buffer[256].© 2009 ANSYS. char *argv[]. and its subsidiaries and affiliates. FILE *fp. Inc. elemid). nodeid). argv. faceid. case 'l': do_loads = 1. if (nnodes < 0) { sprintf (errmsg. verbose &= 3. "filename not specified\n"). /* header . packet = atoi (buffer). argv[argind]). n >= 0. Contains proprietary and confidential information of ANSYS. 27 . getline (). Release 12. &st)) { fprintf (stderr. getline (). "r"))) { sprintf (buffer. All rights reserved. argv[argind]). } *nodeid = atoi (&buffer[2]). testfile).\n"). } if (verbose) { printf ("reading Patran Neutral file from <%s>\n". exit (1). } /* get remaining packets */ while (packet != 99) { /* node */ if (packet == 1) { if (0 != (verbose & 4)) { printf ("reading packet 01 (nodes). } if (NULL == (fp = fopen (argv[argind]. "can't open <%s> for reading". "can't stat <%s>\n". xyz[n] = atof (p)..st_mode & S_IFMT)) { fprintf (stderr. for (n = 2. "<%s> is not a regular file\n". if (stat (argv[argind].packet 25 */ if ((packet = atoi (buffer)) == 25) { getline (). Inc. stdout). fflush (stdout).© 2009 ANSYS. } if (S_IFREG != (st. getline (). Inc. p -= 16. packet = atoi (buffer). getline (). if (verbose) fputs (buffer. fflush (stdout). cfxImportFatal (buffer). } if (NULL == testfile) cfxImportInit (). else { if (verbose) printf ("writing output to <%s>\n". cfxImportTest (testfile). } cfxImportError (print_error). exit (1). and its subsidiaries and affiliates.An Example of a Customized C Program for Importing Meshes into CFX-Pre } if (argind >= argc) usage (usgmsg. n--) { *p = 0.packet 26 */ if (packet == 26) { getline ().1 . argv[argind]). argv[argind]). p = buffer + 48. } /* summary .. } else if (nnodes == 8) { typ = cfxELEM_HEX. buffer). xyz[0]. } lineno++. if (verbose) { printf ("reading packet 06 (loads) as region <%s>. for (n = 0..1 . cfxImportElement ((ID_t)elemid. getline (). if (n == 5 || n == 7 || n == 8) { cfxImpElemType_t typ. loadid = atoi (&buffer[10]).. n = atoi (&buffer[10]). All rights reserved. Inc. } else if (nnodes == 6) { typ = cfxELEM_WDG. . if (loadid != lastid) { sprintf (buffer. nodeid). nnodes = n == 8 ? n : n-1. } else if (nnodes == 5) { typ = cfxELEM_PYR. loadid).An Example of a Customized C Program for Importing Meshes into CFX-Pre } getline (). } else { cfxImportFatal("invalid number of nodes for element. &tmp) || tmp < 1) { cfxImportFatal ("missing or invalid node ID"). fflush (stdout).. } /* element */ else if (packet == 2) { if (0 != (verbose & 2)) { printf ("reading packet 02 (elements).. nlines = atoi (&buffer[18]). } /* distributed loads */ else if (packet == 6 && do_loads) { elemid = atoi (&buffer[2]). } } while (getc (fp) != '\n') . 28 Contains proprietary and confidential information of ANSYS.> 0) getline (). Inc."). n < nnodes. typ. n++) { int tmp. and its subsidiaries and affiliates. cfxImportNode (*nodeid. } elemid = atoi (&buffer[2]). } while (nlines-. verbose &= 1.\n". xyz[1]. "PatranLoad%d".\n"). if (1 != fscanf (fp. nlines = atoi (&buffer[18]). if (nnodes == 4) { typ = cfxELEM_TET. "%d". xyz[2]).© 2009 ANSYS. fflush (stdout). nlines -= 2. } else { nodeid[n] = (ID_t)tmp. } Release 12. cfxImpREG_NODES). /* strip leading and trailing spaces */ buffer[sizeof(buffer)-1] = 0. cfxImpREG_NODES). n < nnodes. lineno++. while (nlines--) getline ().© 2009 ANSYS. Inc. elemid = atoi (&buffer[2]). &buffer[9]). } getline ().\n". getline (). cnt = 0. *p && isspace(*p). } } } while (getc (fp) != '\n') . p = buffer + strlen (buffer). and its subsidiaries and affiliates. 29 . lastid = loadid. &id). Release 12.. fscanf (fp. for (p = buffer. n++) { if (0 == (n % 5)) lineno++. *++p = 0. id. Inc.1 . type. fflush (stdout).An Example of a Customized C Program for Importing Meshes into CFX-Pre cfxImportBegReg (buffer. if (verbose) { printf ("reading packet 21 (group) as region <%s>. &type. nodeid). Contains proprietary and confidential information of ANSYS.. } cfxImportBegReg (p. /* currently only handle type 5 (nodes) in groups */ for (n = 0. } /* named component */ else if (packet == 21) { int cnt. p++) . while (--p >= buffer && isspace(*p)) . /* add if element load flag is set */ if ('1' == buffer[0]) add_face (elemid. if (cnt) cfxImportAddReg (cnt. cnt = 0. fp)) break. if (8 == cnt) { cfxImportAddReg (8. All rights reserved. while (--nlines > 0) getline (). "%d%d". if (5 == type) { nodeid[cnt++] = id. nnodes = atoi (&buffer[10]) / 2. cfxImportEndReg (). } if (NULL == fgets (buffer. sizeof(buffer). } /* all others */ else { nlines = atoi (&buffer[18]). nodeid). p). 31) CFX Def/Res (p. 31) CFX-5. 31) CFX-TfC (p. 32) CGNS (p. "unreferenced nodes". /* finish up and send the data */ if (verbose) { printf ("transferring data. fflush (stdout). } Import Programs The following sections detail the standard import programs currently available within CFX-Pre and their command line equivalents. printf ("%s = %ld\n". "imported regions ".1 . bytes).. } cfxImportDone (). All rights reserved. "wedge elements ". n < 9. "imported elements ". 62) details how to run a mesh import program. "hex elements ".© 2009 ANSYS. putchar ('\n'). bytes = cfxImportTotals (stats). stats[n]). then you may want to run these programs as user-defined mesh import programs. } exit (0). 30 Contains proprietary and confidential information of ANSYS. and its subsidiaries and affiliates.1 (p. If you want to use command line options that cannot be specified through the CFX-Pre User Interface. /* print summary */ if (verbose) { size_t stats[cfxImpCNT_SIZE]. 33) ANSYS FLUENT (p.\n"). Information about importing meshes from the CFX-Pre interface is given in Importing Meshes (p. • • • • • • • • ANSYS (p. 34) Release 12. The executables are located in <CFXROOT>/bin/<os>.. statname[n]. . } fclose (fp). "duplicate nodes ". Inc. "tet elements ". cfxImportError (NULL). n++) printf ("%s = %ld\n".Import Programs packet = atoi (buffer). static char *statname[] = { "imported nodes ". "pyramid elements ". User Import (p. long bytes. 51) in the ANSYS CFX-Pre User's Guide. for (n = 0. 31) CFX-4 (p. "total bytes sent " }. 33) GridPro/az3000 (p. Inc. statname[9]. Echo additional data to stdout during the import. 35) CFX-TASCflow (p.1 results file. must lie in a plane). -f Input file is formatted. Available options are: -v Verbose output. Available options are: -v Verbose output.1 Imports a CFX-5. -c Import blocked-off conducting solid regions as 3D regions. -I Read mesh from the initial timestep in the file. Echo additional data to stdout during the import. Echo additional data to stdout during the import. CFX Def/Res Imports the mesh from a CFX-Solver input or results file.1 . -T<timestep> Read mesh from the timestep specified (Transient files) CFX-4 Imports a CFX-4 grid file. 34) NASTRAN (p. 34) ICEM CFX (p. The external import routine is ImportDef.ANSYS • • • • • I-DEAS (p. -X Import axisymmetric problem with default values in geometry file. -S Display a list of all supported element types. CFX-5. 31 . -L Read mesh from the last timestep in the file. -A <theta> Create a total sector of theta degrees for axisymmetric import. Available options are: -v Verbose output. The external import routine is ImportCFX4. -a <nk> Override the number of planes created in the k direction by nk (for example. Contains proprietary and confidential information of ANSYS. -S Rename multiple symmetry planes with the same name to conform to CFX-Solver requirements (that is. -i Included interfaces in regions. and its subsidiaries and affiliates. Inc. Echo additional data to stdout during the import. The external import routine is ImportANSYS. -E Import Elements of the same type as regions. split theta with nk planes) for axisymmetric import.© 2009 ANSYS. 34) PATRAN (p. All rights reserved. Inc. -l Include blocked-off solid regions as 3D regions. -3 Include USER3D and POROUS regions as 3D regions. -C Read coordinates as being in cylindrical coordinates. -A Import ANSA parts as regions. Release 12. The external import routine is ImportCFX5. 35) ANSYS Imports an ANSYS file. -u Input file is unformatted (Fortran). Available options are: -v Verbose output. . SUN . IBM).Sun 32-bit IEEE. -f Input file is formatted. BSIEEE .native Convex floating point format.© 2009 ANSYS. IBM . Windows .32-bit Windows.generic 32-bit byteswapped IEEE machine.1 . DOS .native Convex floating point format. CONVEX . -b <file> Use file as BFI file name instead of default name. CRAY . HP . DOS . Echo additional data to stdout during the import. HP. HP . Inc. CONVEX .DOS 16-bit byte-swapped IEEE.generic 32-bit IEEE machine.IBM 32-bit IEEE. IBM . BSIEEE . The argument machine type is case insensitive. The currently recognized machine types are: • IEEE . Sun. -r Read regions from BFI file. IBM).generic 32-bit IEEE machine. ALPHA . ALPHA . Sun.IBM 32-bit IEEE. SUN . Compaq Tru64 UNIX . The currently recognized machine types are: • • • • • • • • • • • • IEEE .Cray 64-bit format.Iris 32-bit IEEE. Sun. HP.CFX-TfC -M <machine type> Set the machine type in the case of a binary or unformatted file so that data conversion may be done if needed. The argument machine type is case insensitive.generic 32-bit IEEE machine.Iris 32-bit IEEE.HP 32-bit IEEE. -M <machine type> Set the machine type in the case of a binary or unformatted file so that data conversion may be done if needed. The default file format is 32-bit IEEE (Iris.Compaq Tru64 UNIX 32-bit byte-swapped IEEE. Available options are: -v Verbose output.Compaq Tru64 UNIX Alpha 64-bit byte-swapped IEEE. IRIS . and its subsidiaries and affiliates. The default file format is 32-bit IEEE (Iris. IRIS .Sun 32-bit IEEE. CRAY . Release 12. Inc.HP 32-bit IEEE. 32 Contains proprietary and confidential information of ANSYS. HP. The default file format is 32-bit IEEE (Iris. -M <machine type> Set the machine type in the case of a binary or unformatted file so that data conversion may be done if needed. -u Input file is unformatted (Fortran). The currently recognized machine types are: • • • • • • • • • • • • IEEE . IBM). CFX-TfC Imports a CFX-TfC 1. Windows .32-bit Windows. The external import routine is ImportGEM.DOS 16-bit byte-swapped IEEE.generic 32-bit byteswapped IEEE machine.3 mesh file. Compaq Tru64 UNIX . and only the first 2 characters are needed (any others are ignored).Cray 64-bit format. All rights reserved.Compaq Tru64 UNIX Alpha 64-bit byte-swapped IEEE.Compaq Tru64 UNIX 32-bit byte-swapped IEEE. and only the first 2 characters are needed (any others are ignored). HP . Contains proprietary and confidential information of ANSYS... SUN . it must always remain in this position relative to the created files). IRIS .cas or . the import filter will only currently read "Pipe". The method for running this is: SplitCGNS.cgns each containing a single problem which can then be selected for import via the normal method. Compaq Tru64 UNIX ./.msh file. Windows . -P Do not add the Zone name as a prefix to any region being defined.native Convex floating point format. -E Import each Element Section as a separate region.cgns and basename_Elbow. -I Import each side of a connection as a separate region.exe [ -l ] <filename> <basename> If the file contains two problems called "Pipe" and "Elbow".Iris 32-bit IEEE. CGNS Imports a CGNS file The external import routine is ImportCGNS. -b Read a grid from the specific CGNS base. All rights reserved.1 ./example.DOS 16-bit byte-swapped IEEE. -I Import interior boundary conditions. Inc. SplitCGNS.generic 32-bit byteswapped IEEE machine. The external import routine is ImportFluent. if when SplitCGNS was run the original file was in . but using SplitCGNS will produce two files called basename_Pipe. 33 . The created file does not therefore need to duplicate data.© 2009 ANSYS. Echo additional data to stdout during the import. The argument machine type is case insensitive.Cray 64-bit format. CONVEX . The import routine will read the mesh information from the . Echo additional data to stdout during the import. Available command line options are: -v Verbose output. Specifying the "-l" option "links" the part of the data in the original file to the created file using a relative pathname.Compaq Tru64 UNIX 32-bit byte-swapped IEEE. (default) -c Read BOCO information as 2D regions.cgns. CRAY . The "-l" option should only be used if the original file and resulting files are going to be kept relative to each other (that is. IBM . ALPHA .exe The SplitCGNS. DOS .HP 32-bit IEEE.Compaq Tru64 UNIX Alpha 64-bit byte-swapped IEEE. and only the first 2 characters are needed (any others are ignored).Sun 32-bit IEEE. and its subsidiaries and affiliates. Release 12. -f Import Family Information as regions. ANSYS FLUENT Imports ANSYS FLUENT msh and cas files.IBM 32-bit IEEE.32-bit Windows.exe program will take a single CGNS file and split it into multiple files on a "file per problem basis". -B Read all CGNS bases. Inc.CGNS • • • • • • • • • • • BSIEEE . Available options are: -v Verbose output. else the default name UnnamedRegionX with the X replaced by a number will be used. Echo additional data to stdout during the import. Echo additional data to stdout during the import. Available options are: -v Verbose output. resulting in duplicate nodes at the block interfaces. Available options are: -v Verbose output. If the file is not found.GridPro/az3000 GridPro/az3000 Imports a GridPro/az3000 grid and connectivity file from Program Development Corporation (PDC). The external import routine is ImportPDC. Echo additional data to stdout during the import. -c <connfile> Set the name of the connectivity file associated with the grid file to connfile. and nodes (type 5) from packet 21 (named groups) as regions. -l Import elements in a PERMANENT group as a 3D region. If the boundary condition is named in the connectivity file. -P Read coordinate data from a binary file as double precision. -p Include periodic boundary conditions as regions. Reads datasets 781 and 2411 (nodes) as nodes. the import routine will look for a file named conn.tmp.1 . the interface information in the file will be used to eliminate the duplicate nodes at block interfaces. 34 Contains proprietary and confidential information of ANSYS. ICEM CFX Imports a file written for CFX by ICEM Tetra. All rights reserved. -3 Import grid blocks as 3D regions I-DEAS Imports an I-DEAS Universal file from SDRC. Available options are: -v Verbose output. -i Ignore the connectivity file. Setting this flag will result in these being imported as regions. All other datasets are read. then the grid file name extension will be replaced by conn and the new file checked for. 780 and 2412 (elements) as elements. -n Import nodes in a PERMANENT group as a 2D region. If a connectivity file is not found. The external import routine is ImportIDEAS. but not processed. A command line option is available to read packet 06 (loads) as regions also. and if found will use it. Echo additional data to stdout during the import. The import routine will attempt to determine the connectivity file associated with the grid file by appending the extension conn to the grid file name. If a connectivity file is found. You may then want to eliminate these duplicate nodes with the command line option (-d or -D). These are not normally included in the import. Inc.© 2009 ANSYS. but not processed. Release 12. and its subsidiaries and affiliates. The external import routine is ImportPatran. All other packets are read. then that name will be used for the region name. Inc. Reads packet 01 (nodes) as nodes. Duplicate nodes will result and no regions will be imported. and boundaries conditions will be imported as regions into CFX. The external import routine is ImportICEM. PATRAN Imports a PATRAN Neutral file. Available options are: -v Verbose output. . packet 02 (elements) as elements. A command line option (-c) is also available to explicitly name the connectivity file. or the command line option to ignore the connectivity file is given (-i). If neither of these are found. -f Import faces in a PERMANENT group as a 2D region. -q Read from the property file -P <propfile> Set the name of the property file associated with the grid file to propfile. then only the grid file will be imported. and nodes (type 7) from datasets 752 and 2417 (permanent groups) as regions. The regions will be assigned the name PatranLoadX where the X is replaced by the load ID number. and its subsidiaries and affiliates. The import routine will read the mesh information from the GRD file and automatically remove duplicate nodes where interfaces are defined and are 1:1.NASTRAN -l Import packet 06 (distributed loads) as regions. -g <file> Specifies gci file to import. -i Ignore the blockoff file (BCF).1 . 35 . The external import routine is ImportGRD. -V More verbose output. 58) in the ANSYS CFX-Pre User's Guide. -o Old style 2. The external import routine is ImportMSC. see CFX-TASCflow Files (p.4 format. -u Fortran unformatted GRD file. Inc. Currently reads only nodes (GRID). NASTRAN Imports a NASTRAN file. -s Import PSOLID datasets as 3D regions. -b <file> Specifies bcf file which contains blocked-off regions (boundary condition information is ignored). Available options are: -v Verbose output. tet (CTETRA) and hex (CHEXA) elements. Echo additional data to stdout during the import. see CFX-TASCflow Files (p. -l Import PLOAD4 datasets as 2D regions. Release 12. -3 Import labelled 3D regions. 58) in the ANSYS CFX-Pre User's Guide. CFX-TASCflow Imports TASCflow Version 2 files.© 2009 ANSYS. For details. -f Formatted (ASCII) GRD file. All rights reserved. -c Ignore GCI file. For details. Available command line options are: -v Verbose output. Echo additional data to stdout during the import. Inc. Contains proprietary and confidential information of ANSYS. Release 12. .1 . All rights reserved. Inc.© 2009 ANSYS. and its subsidiaries and affiliates. Contains proprietary and confidential information of ANSYS. Inc. and its subsidiaries and affiliates. 50) Details of the Mesh Export API (p. EnSight and Fieldview. see An Example of an Export Program (p. 2.© 2009 ANSYS. writes a geometry file (ignoring pyramid elements) and several files containing results. 37 . ready for input into post-processing software other than CFD-Post. Compile your C program. 50) Linking Code with the Mesh and Results Export API (p. The general steps to follow are: 1. it may be worth contacting a system administrator to find out if such a format has already been defined. The example program is a reasonably simple example of an export program. An Example of an Export Program The following is an annotated listing of the C source code for a reasonably simple example of a customized Export program. see Compiling Code with the Mesh and Results Export API (p. This chapter describes: • • • • Creating a Customized Export Program (p. see Using a Customized Export Program (p. which opens a CFX results file. 50). 51) Creating a Customized Export Program The mesh and results contained within an ANSYS CFX results file can be exported in many formats. 37). Information on using such a program is given in Using a Customized Export Program (p. one is given in the next section. Numerous keywords are required for development and use of custom export files. Link the C program into the CFX code. After the program listing. so if other ANSYS CFX users at a site regularly use a different post-processor.Chapter 3. File Header The file header uses several #include entries. a sample of the output produced is shown. For details. it can be used by any number of users. Inc. Mesh and Results Export API This document describes how to create a custom program for exporting mesh and results data. you would write a customized export program that calls routines from the Export Application Programming Interface (API). Use the program. Contains proprietary and confidential information of ANSYS. 150). 50). Create a file that contains instructions needed to build the format in C. For details. 146). To define a new format.h> #include <string. 37) Compiling Code with the Mesh and Results Export API (p. The first set includes standard header files. However. 150). because it involves at least some knowledge of C or C++ programming language. where CFX is the directory in which CFX is installed. All rights reserved. 3.1 . use the export API. MSC/PATRAN. For details. see cfx5export Arguments (p. Inc. #include <stdio. see Linking Code with the Mesh and Results Export API (p. For details.c. An example source routine can be used as the basis of a customized program. This is most easily done by editing the template file provided (which is written in C). The full source code is available for use as a template and is located in CFX/examples/ExportTemplate. For details. 4. Once an export program has been created. this is recommended only for advanced users. To do this.h> Release 12. errmsg[256]. All rights reserved. zone = 0. NULL }.".v## where ## is the variable". The variables level. n. int nTimeDig = 1. length. "geometry file will be written to <basename>. char baseFileName[256]. Release 12. The Template". dim.h" #include "getargs. . 50).h as are all variables and functions starting with the letters cfx. Inc. bndfix and bnddat are used for setting the default values for the various parameters that can be set on the command line of the program.h" Obtaining CFX-Mesh and Results Export API header files is described in more detail. Main Program Initialization As is standard. infoOnly = 0. void main (int argc. For details. zone. nvalues. namelen. " -i = include boundary node only data". /* number of digits in transient file suffix */ char zoneExt[256]. t. char *argv[]) { char *pptr. alias = 1. " <basename> is the base filename for Template file output. bnddat = 0. alias. " -f = get info on the res_file (No output is created)". all timesteps". The variable cfxCNT_SIZE and the types cfxNode and cfxElement are defined in the header file cfxExport. Inc. int timestep = -1.".all the domains". " are exported)" " -c = use corrected boundary node data". Allowed Arguments The definition of allowed arguments appears as: static char options[] = "u:d:t:cif". int ts. nvectors. and its subsidiaries and affiliates.res. fileName[256]. 37). #include "cfxExport. and the variables to".© 2009 ANSYS. int nnodes. counts[cfxCNT_SIZE]. "number and s indicates a scalar and v a vector.h> #include <io. see Linking Code with the Mesh and Results Export API (p. t2.geom. "If not specified. The following piece of code simply defines the message that is printed if the user enters incorrect options to the program. nelems. nscalars. it defaults to ‘res_file'. static char *usgmsg[] = { "usage: ExportTemplate [options] res_file [basename]". 38 Contains proprietary and confidential information of ANSYS.s## or <basename>. int i.h> The second set includes cfx5export header files. int level = 1. the variables argc and argv are the number of arguments and a pointer to the argument list.An Example of an Export Program #include <stdlib. bndfix = 0. the". /* zone extension added to the base filename */ int isTimestep = 0. " options are:". For details. " -t<timestep> = timestep of interest (if set to -1.1 . " -u<level> = user level of interest". "results file to <basename>. see Mesh and Results Export API (p. " -d<domain> = domain of interest (default is 0 . " are combined into a single domain)". t1. "<basename>. isTimestep = 1. NULL). /* used in transient file specification */ FILE *fp. The following line prints an error message if there are not enough arguments to proceed. /* time value in the single timestep mode */ char *wildcard = { "******" }. then corrected values are used. break. and that it can be read by the export program. bnddat determines whether variables that contain meaningful values only on the boundary (such as Yplus) are exported or not. float *var. /* CFX-5 results file */ if (argind >= argc) Release 12. The variable alias determines whether the variables are referred to by their long names or short names. Finally. Contains proprietary and confidential information of ANSYS. break. } } After this. alias. cfxElement *elems. the export program exits.© 2009 ANSYS. zone. The default here is for short names to be used because some post-processors need variable names to contain no spaces. 37). break. then these variables are exported.if bndfix is set to 1. The following piece of code reads the specified options and assigns values to certain variables accordingly. then getargs prints an error message and the export program stops. case ‘i': bnddat = 1. All rights reserved. bndfix and bnddat are used for setting the default values for the various parameters that can be set on the command line of the program. if bnddat is set to 1. case ‘d': zone = atoi (argarg). The variables level. case ‘c': bndfix = 1. The variable bndfix determines whether the variables are exported with corrected boundary node values . cfxNode *nodes. break. Inc. argv. Inc.0. the level variable contains the user level specified. If this is not the case. case ‘t': timestep = atoi (argarg).An Example of an Export Program float timeVal = 0. break. The zone variable contains the domain number that you specified. and its subsidiaries and affiliates. 39 . but you are encouraged to use long variable names wherever possible. All results are output if they are of this user level or below it. options)) > 0) { switch (n) { case ‘u': level = atoi (argarg). If an invalid or incomplete option is specified. if (argc < 2) cfxUsage (usgmsg. break.1 . see Mesh and Results Export API (p. case ‘f': infoOnly = 1. Checking File Names The following code checks to make sure that a CFX results file has been specified.h as are all variables and functions starting with the letters cfx. For details. The variable cfxCNT_SIZE and the types cfxNode and cfxElement are defined in the header file cfxExport. while ((n = getargs (argc. n = cfxExportInit (argv[argind]. nt = cfxExportTimestepCount(). . 0)) { fprintf (stderr. and its subsidiaries and affiliates. A basename name may be specified in another directory (for example. ‘/'))) strrchr (baseFileName.© 2009 ANSYS. i. later in the code this basename without the preceding directory information is required (in this example “output”). i++) printf(" %d %s\n". if (NULL != (pptr = strrchr pptr++. ‘\\'))) The following code checks that the results file that will be produced by the export program will not overwrite an existing results file. The number of domains to be exported is also determined so that the format of the exported file includes the appropriate suffix. exit (1). /* base file name */ if (argind + 1 < argc) strcpy (baseFileName. if (infoOnly) { int nt. Inc. argv[argind]). argv[argind+1]). The variable n is set to equal the number of zones in the results file. else pptr = baseFileName. “. n).1 . i <= nt. } Opening the CFX Results File The following code prints a message to the screen telling you that the program is reading the results file. printf("%d timesteps:\n". "Template res file would overwrite CFX results file\n"). which must always be called before any of the other export routines.An Example of an Export Program cfxUsage (usgmsg. 40 Contains proprietary and confidential information of ANSYS. However. If one was not specified. then it defaults to the name of the results file specified. If the -f option has been selected. argv[argind]). i <= n. else strcpy (baseFileName. NULL). All rights reserved. fprintf (stderr. information about the results file will be displayed. } The following code writes the basename specified to the character array baseFileName. Finally. and so the pointer pptr is assigned to point to the first character of this name. argv[argind]). /* open CFX-5 results file */ printf ("\nreading CFX results from <%s>\n". for(i = 1. cfxExportZoneName(i)).res". /* don't overwrite results file */ sprintf (fileName. if(nt) { for(i = 1. if (0 == strcmp (argv[argind]. if (access (argv[argind]. nt). a check is made to make sure that the zone (if any) that you specified in the program options is a valid zone for this results file. "result file <%s> does not exist\n". Inc. fileName)) { fprintf (stderr. "Need to select new Template output base file name\n"). baseFileName).. exit (1). printf("\n%d domains:\n". (baseFileName./template/output”). "CFX-5 results file not specified"). else if (NULL != (pptr = pptr++. Release 12. i++) printf(" %d\n". } cfxExportDone(). cfxExportTimestepNumGet(i)). "%s. It then calls cfxExportInit. and its subsidiaries and affiliates. /* count number of digits needed to fit any zone number */ f = (float) n. cfxExportSetVarParams(bndfix. Timestep Setup The following code determines whether all of the timesteps. The following code is ignoring any pyramid elements (elements with 5 nodes) and decreases nelems by the number of pyramid elements. if (counts[cfxCNT_PYR]) { printf ("%d pyramid elements found . timestep). nZoneDig.*d". if(timestep == -1) { printf("processing all timesteps\n"). } else { int isFound = 0. a specific timestep or the final timestep (steady-state) have been selected for export. if(isTimestep && timestep == -1 && !cfxExportTimestepCount()) { isTimestep = 0. the program exits with return code -1. counts[cfxCNT_PYR]). nelems = cfxExportElementCount(). for(i = 1. t2 = cfxExportTimestepCount() + 1. } /* determine the zone suffix for the export files */ strcpy(zoneExt. zone). } } if (cfxExportZoneSet (zone. It then checks to make sure that neither the number of nodes nor the number of elements is zero. i++) if(cfxExportTimestepNumGet(i) == timestep) { Release 12. zone). Inc.1 . i <= cfxExportTimestepCount() + 1. float f. level). if(n != 1) { float f. counts) < 0) cfxExportFatal ("invalid zone number"). while((f /= 10) >= 1) nZoneDig++.© 2009 ANSYS. } if (!nnodes || !nelems) cfxExportFatal ("no nodes and/or elements"). The first two lines focus on the number of nodes in the zone and the number of elements in the zone. } else { printf ("processing domain %d\n". } if(isTimestep) { int i. nnodes = cfxExportNodeCount(). nZoneDig.An Example of an Export Program exit (0). int nZoneDig = 0. sprintf(zoneExt. if so. t1 = 1. "_d%*. 41 . nelems -= counts[cfxCNT_PYR]. Contains proprietary and confidential information of ANSYS. ""). printf("processing timestep %d\n". All rights reserved.they are being ignored\n". Inc. if(zone == 0) { printf ("processing all domains\n"). cfxExportFatal (errmsg). fprintf( fp.geom.". "w+"))) { sprintf (errmsg. if (NULL == (fp = fopen (fileName. nodes++) { fprintf( fp. /* write header fprintf( fp.© 2009 ANSYS. " \n"). t1 = t2 = cfxExportTimestepCount() + 1. "can't open <%s> for output". "%8d %12. } printf ("writing Template Geometry file to <%s>\n".5e %12. nodes->z ). followed by the three coordinates of that node.geom". nnodes ).1 . cfxExportFatal (errmsg). } } /* count number of digits needed to fit any timestep number */ f = (float) cfxExportTimestepCount(). and its subsidiaries and affiliates. the cfxExportNodeFree routine frees the memory that was used to store the node data. printing an error if it can't be opened for any reason. t1 = t2 = i. isFound = 1. fprintf( fp. } if(!isFound) { sprintf(errmsg.. } Geometry File Output The following code opens the geometry file basename.An Example of an Export Program timeVal = cfxExportTimestepTimeGet(i). . n++. fprintf( fp. and finally the word “done” is printed on the screen to alert you that it has finished writing the node data. For each node. fileName). } else { timeVal = cfxExportTimestepTimeGet(cfxExportTimestepCount() + 1). The pointer nodes is initialized to point at the data for the first node and the node data is written into the geometry file. n < nnodes. for (n = 0. "element id off\n"). Release 12.. The following code writes first the word “coordinates” and the number of nodes that will be written. A message is then displayed informing the user that the application is writing the geometry file. baseFileName). " "Use -f to see the list of valid timesteps. fileName).5e\n". fprintf( fp. fflush (stdout). "node id given\n"). printf (" writing %d nodes . n + 1. Inc. /* write nodes */ fprintf( fp.\n". Inc. "%s. nnodes). nodes = cfxExportNodeList().5e %12. */ "Template Geometry file exported from CFX\n"). while((f /= 10) >= 1) nTimeDig++. All rights reserved. Note that n ranges between 0 and nnodes-1. When it has finished. break. "%8d\n". The header of this file is shown after the program listing. timestep). nodes->y. 42 Contains proprietary and confidential information of ANSYS. /* Template geometry output */ sprintf (fileName. "coordinates\n"). This program adds 1 to each node number so that the nodes in the geometry file are numbered between 1 and nnodes. timestep = cfxExportTimestepNumGet(cfxExportTimestepCount() + 1). "\nTimestep %d not found. nodes->x. a node number is written. the same procedure is followed. } } } For wedges (triangular prisms) and hexahedral elements. This may need to be done if a post-processor has a different convention for node order than the one that the cfx5export node routines have. there is a slight difference in the way that the fprintf line is written for hexahedral elements. counts[cfxCNT_WDG] ). Firstly. n++.An Example of an Export Program } cfxExportNodeFree(). The order the nodes are written in will affect which node is connected to which. then loop over its four vertices and write their node numbers to the geometry file. } } /* hexes */ fprintf( fp. Inc. elems->nodeid[i]). elems is set to point to the list of elements stored in the results file. /* wedges */ fprintf( fp. if (counts[cfxCNT_TET]) { elems = cfxExportElementList(). the following step is carried out: “If the element is a tetrahedron. } putc (‘\n'. i++) fprintf (fp. fp). Assuming this.". 56).. "volume elements\n"). the word “tetra4” is written to the file. Contains proprietary and confidential information of ANSYS. if (counts[cfxCNT_WDG]) { elems = cfxExportElementList(). for (n = 0.1 . printf (" done\n"). some general information is written. n++. i < elems->type. fp). /* tets */ fprintf( fp. printf (" writing %d elements. fprintf( fp. for (n = 0. i++) fprintf (fp. "%8d\n". For each element. "hexa8\n"). Release 12. All rights reserved. fflush (stdout). "%8d\n". and its subsidiaries and affiliates. "penta6\n"). The following code is executed only if the number of tetrahedral elements is non-zero.© 2009 ANSYS. This is because the order that the element nodes are written to the geometry file is different to the order in which they were read from the results file. Next. followed by the number of tetrahedral elements written. Then the data for each element type is written in turn. counts[cfxCNT_TET] ). For tetrahedral elements. "%8d". elems++) { if (cfxELEM_WDG == elems->type) { for (i = 0. i < elems->type. then start a new line (ready for the next set of data). /* write elements */ fprintf( fp. nelems). fprintf( fp. "tetra4\n"). n < nelems. n < nelems. 43 . The node ordering for exported elements is illustrated in cfxExportElementList (p. "%8d". elems++) { if (cfxELEM_TET == elems->type) { for (i = 0. Inc. The index n loops over all the elements. the data for each element must be written. "part 1\n" )..” The output produced can be seen in the examples of the exported files in the next section. putc (‘\n'. However. fprintf( fp. elems->nodeid[i]). &dim. Have a dimension of 1 (scalar variable) or 3 (vector variable) and. &i).© 2009 ANSYS. elems->nodeid[1]. 63). the Template results file does not contain any actual values of results. 44 Contains proprietary and confidential information of ANSYS. Inc. if ((nvalues = cfxExportVariableCount(level)) > 0) { for (n = 1. Then it counts the number of scalar and vector variables that will be exported. 2. Inc. a variable must: 1. n++) { cfxExportVariableSize (n. n < nelems. fclose (fp). printf (" done\n"). cfxExportElementFree(). alias)). the code checks that there is a nonzero number of variables that have the specified user level.An Example of an Export Program fprintf( fp. It simply contains information about how many variables there are and in which file each is stored. else nvectors++. if ((1 != dim && 3 != dim) || (length != nnodes && length != bnddat)) continue. All rights reserved. elems->nodeid[4]. Template Results File Despite its name. Release 12. The first job is to make sure that there are some results for export. "%8d\n". which translated to setting bnddat = 1 when the arguments were processed). elems->nodeid[7]. . &length. i = strlen (cfxExportVariableName (n. n <= nvalues. Once results are identified. counts[cfxCNT_HEX] ). the export program exits. for (n = 0. } } if (0 == (nscalars + nvectors)) { cfxExportDone (). if (namelen < i) namelen = i. Review the cfxExportVariableSize routine if this logic is unclear. and its subsidiaries and affiliates. elems->nodeid[5]. the code calculates the variable namelen. elems++) { if (cfxELEM_HEX == elems->type) fprintf (fp. "%8d%8d%8d%8d%8d%8d%8d%8d\n". If there are no vector or scalar variables to be exported. First. /* output results file */ nscalars = nvectors = namelen = 0. To be exported. elems->nodeid[0]. elems->nodeid[3]. which is the length of the longest variable name to be exported (the alias variable was set when processing the arguments passed to the export program. elems->nodeid[2]. n++. } } Then the geometry file is closed and the memory occupied by the element data is freed. if (1 == dim) nscalars++. For details. elems->nodeid[6]). if (counts[cfxCNT_HEX]) { elems = cfxExportElementList(). see cfxExportVariableSize (p.1 . Either be a variable with useful values everywhere in the zone or be a variable that has values only on the boundaries (in which case it will be exported only if you asked to “include boundary node only data” by specifying the option -i when starting the export program. and depends upon whether you wanted to use long names or short names). cfxExportVariableName(n.2d %s\n". zoneExt.2d %s\n". if (NULL == (fp = fopen (fileName. cfxExportFatal (errmsg). Next.2d %s\n". "%s%s. The number of scalar and vector variables are written to the file. } fprintf( fp. zoneExt. else fprintf (fp. baseFileName). } The following code checks that the results file can be opened for writing to. requires) that are always the same for any export of this kind. alias)). a line is written that contains the filename where the scalar will be written. "%s%s_t%d. and its subsidiaries and affiliates. Release 12. &dim. else if(t1 == t2) fprintf (fp. cfxExportVariableName(n.2d %s\n".© 2009 ANSYS. n. For details. pptr.t1 + 1 ). see Checking File Names (p. and then the name of the variable. fprintf( fp. pptr. "\n"). fflush (stdout). nvectors ). zoneExt. "w+"))) { sprintf (errmsg. zoneExt.v%2. nscalars. t2 . if (1 == dim && (length == nnodes || length == bnddat)) if(!isTimestep) fprintf (fp. fileName). cfxExportTimestepNumGet(t1). Note that the filename is not the basename. n++) { cfxExportVariableSize (n. "%s. if (3 == dim && (length == nnodes || length == bnddat)) if(!isTimestep) fprintf (fp. followed by some numbers (which EnSight. if(!(i % 6)) fprintf( fp. n <= nvalues. &length. n++) { cfxExportVariableSize (n. pptr.s%2. &length. for each scalar variable. and exits if not. i <= t2.1 . fprintf( fp. sprintf (fileName. &dim. &i). All rights reserved. "%d\n". n.s%2. if(isTimestep && t1 != t2) fprintf( fp. 45 . for example. } printf ("writing Template results file to <%s>\n". "%13.4e". for(i = t1.*s. alias)). "%s%s. "%s%s_t%d. else if(t1 == t2) fprintf (fp. n. fileName). zoneExt. Inc. alias)). but the basename with all the directory structure (if any) stripped off the front. nTimeDig. cfxExportTimestepNumGet(t1). i++) { fprintf( fp. cfxExportVariableName(n. 39). Inc. pptr. "%s%s_t%*. Contains proprietary and confidential information of ANSYS. "0 1\n"). } } The same information is then written for each vector variable and the Template results file is closed. if ( nvectors ) { for (n = 1. &i). alias)). wildcard. nTimeDig. cfxExportVariableName(n.v%2. "%d %d 0\n". "can't open <%s> for writing". This is done because these file will be written in the same directory as this Template results file. n.res". cfxExportTimestepTimeGet(i)). if ( nscalars ) { for (n = 1. so there is no need for directory information.An Example of an Export Program exit (0). n <= nvalues. pptr.2d %s\n". n. "\n").s%2. *s.%c%2. "w+"))) { sprintf (errmsg. and its subsidiaries and affiliates. Each file with an extension containing a letter “s” contains a scalar variable. baseFileName. baseFileName. Inc. zoneExt. alias). t <= t2. baseFileName. n. After each variable. } } fclose( fp ). cfxExportVariableName(n.v03.2d %s\n". which enable access to boundary condition data. nTimeDig. "%s%s. } printf (" %-*s -> %s . "%s%s_t%d. 60) /* output each timestep to a different file */ for(t = t1. n).1 . n). 57) Volume Routines (p. Inc. Which variable is written to each file is tabulated in the Template results file that has just been written. <basename>. and frees up any remaining memory.2d". Creating Files with Results for Each Variable The results for each variable are written to separate files. "%s%s_t%*. zoneExt. inserting a new line every six values. Note This program makes no use of any of the region routines. After all the variable files have been written.*d.2d". "%s%s_t%*. Continuing. alias)). which close the CFX results file. else fprintf (fp. fileName). alias)). 1 == dim ? ‘s' : ‘v'. for example.© 2009 ANSYS.v%2.2d". ts. 46 Contains proprietary and confidential information of ANSYS. "%s\n". called <basename>. Release 12. nTimeDig. writing them to the file. and then loops through all the values. nTimeDig. cfxExportFatal (errmsg). It checks to make sure that the variable information can be read. 1 == dim ? ‘s' : ‘v'.s01.s02.%c%2. it writes to the screen where it is putting the variable. <basename>. the memory used to store that variable is restored. The program then exits.. cfxExportVariableName(n. pptr. . zoneExt. • • Region Routines (p. namelen. fflush (stdout). n). after you decide that it should be exported . "can't open <%s> for writing\n". All rights reserved. } /* build file name and open file */ if(!isTimestep) sprintf( fileName. and (assuming it can) then builds the filename and checks to see if it can be opened. The following code reads the information for each variable. the program calls the cfxExportDone routine. t++) { ts = cfxExportTimestepNumGet(t). nTimeDig. nor the volume routines that enable access to the subdomains that are defined for a problem. cfxExportVariableName(n. else sprintf( fileName. fprintf( fp..".the logic is very similar to that used when counting the relevant variables when creating the Template results file. zoneExt. alias)). else if(t1 == t2) sprintf( fileName. This routine must be the last call to any of the API routines. The marked if loop executes if the variable needs to be exported. if(cfxExportTimestepSet(ts) < 0) { continue. t-1. 1 == dim ? ‘s' : ‘v'.An Example of an Export Program cfxExportVariableName(n. if (NULL == (fp = fopen (fileName.%c%2. fileName). length = nnodes * dim. and each with a “v” contains a vector variable. wildcard. see: • • • example.geom> writing 2365 nodes . done Five files are produced: the geometry file example. No timesteps or domains were specified.1 .. Inc. 48) example. temperature and velocity.. } Example of Output Produced If the export program is correctly compiled and run.s02 . *var ). done writing 11435 elements..51683e-07 3 2. which contain the results for pressure.geom..00000e+00-6.Example of Output Produced for ( i = 0. done Velocity -> example. 48) example.geom (p. This is in a file named file. see Using a Customized Export Program (p.res> writing variable output files Pressure -> example.s01 .v03. 150).geom The content of this file appears as: Template Geometry file exported node id given element id off coordinates 2365 1 2. fp )..00000e+00 . done writing Template results file to <example. i < length.. } if ( 0 != ( nvalues % 6 ) ) putc( ‘\n'. and three variable files called example. the Template results file example.. var++ ) { fprintf( fp. i++. The following is displayed on screen: reading CFX results from <file.00000e+00 0.s01 (p.v03 . fp).res.res (p. Inc. } } } /* loop for each timestep */ cfxExportDone(). and its subsidiaries and affiliates. 47) example. printf (" done\n"). fclose( fp ).00000e+00 0.© 2009 ANSYS.. the following output is obtained.5e ".00000e+00 Release 12. For details.. For details.s02 and example.. exit (0).00000e+00 2.res. All rights reserved. if ( i && 5 == (i % 6) ) putc (‘\n'. temperature and velocity. Contains proprietary and confidential information of ANSYS. In this example. example.res> processing all domains writing Template Geometry file to <example.00000e+00 2-2. cfxExportVariableFree (n). and the basename was specified as an example. 47 from CFX 0. respectively.00000e+00 0.s01. the CFX results file contains three variables at user level 1: pressure. done Temperature -> example. "%12. 44755e+04 1.v03 Velocity example..h> <ctype..37959e+04 Source Code for getargs. . Inc.c The following code is the C code that defines the functions cfxUsage and getargs.22610e-01 2364 1.18877e-01 4.34786e+04 1..00000e+00 5. .51683e-07 2.h" Release 12.34859e+04 1..30703e-01 1.s02 Temperature example.Source Code for getargs.h> <string.0 0 1 example...00000e+00 1.. You do not need to include this code with your custom export program (it is automatically linked in if you use the compiler as described in the next section)..23515e+00 part 1 volume elements tetra4 11435 754 230 755 216 756 212 ..44777e+04 1. .37733e+04 1.44118e+04 1.02491e-01 2363-1. .44130e+04 1.00000e+00 5 3.43350e+04 1.66598e-01 2..12115e+00-3...00000e+00-6... ...h> "getargs. 2365 496 penta6 0 hexa8 0 12 8 125 145 122 215 475 474 example.. All rights reserved.36924e+00 4.res The content of this file appears as: 2 1 0 1 0.42748e+04 1...43425e+04 1.© 2009 ANSYS.1 ..37352e+04 1.s01 The content of this file appears as: Pressure 1.38487e+00 2.c 4-2.22588e-01 2365-3. #include #include #include #include <stdio. 48 Contains proprietary and confidential information of ANSYS.39092e+04 1.24139e+04 1.42621e+04 1.38639e+04 1.13337e+00 2. and its subsidiaries and affiliates.... .78359e-01 1. ..37626e+04 .40699e+04 1.. 2362-1.. 1.. Inc.s01 Pressure example.00000e-01 . both of which are called by the example listing above. argopt). argv. Inc. Contains proprietary and confidential information of ANSYS. *errmsg. } /* check for an argument */ if (*++oli != ‘:') { /* don't need argument */ argarg = NULL. Release 12.getargs --------------------------------------------------* get option letter from argument vector or terminates on error * this is similar to getopt() *----------------------------------------------------------------------*/ int argind = 0. errmsg). errmsg) char **usgmsg. /* end of arguments */ if (++argind >= argc || ‘-' != argv[argind][0]) return (0). "invalid command line option `%c'\n".© 2009 ANSYS. if (nextarg) { /* update scanning pointer */ nextarg = 0. NULL != usgmsg[n]. n++) fprintf (stderr. } /* check for valid option */ if ((argopt = *place++) == ‘:' || (oli = strchr (ostr. /* initialisation */ if (!argind) nextarg = 1.Source Code for getargs. char *errmsg) #else usgmsg. if (!*place) nextarg = 1. char *ostr) #else argc. exit (NULL != errmsg). #endif { int n. #endif { int argopt.c /*---------. All rights reserved. usgmsg[n]). char *oli. if (NULL != errmsg) fprintf (stderr. ostr) int argc. char **argv. exit (1). "ERROR: %s\n". } /*---------. /* index into argv array */ char *argarg. for (n = 0. 49 . "%s\n". *ostr. static int nextarg. static char *place. argopt)) == NULL) { fprintf (stderr.usage -------------------------------------------------* display usage message and exit *-------------------------------------------------------------------*/ void cfxUsage ( #ifdef PROTOTYPE char **usgmsg. Inc. /* pointer to argument string */ int getargs ( #ifdef PROTOTYPE int argc. and its subsidiaries and affiliates. char **argv.1 . place = argarg = &argv[argind][1]. With the exception of bufferoverflowu. 50 Contains proprietary and confidential information of ANSYS.1 .a (on UNIX/Linux) libpgtapi. } return (argopt). } argarg = place.lib (on Windows).lib.lib (on Windows). . but use icc compiler -m64 -q64 (the linker may also need -b64) Linking Code with the Mesh and Results Export API In order to build a customized export utility.lib (on Windows).lib (on Windows).0W +DA2.a (on UNIX/Linux) libcclapilt. and its subsidiaries and affiliates. Inc. } place = argv[argind].a (on UNIX/Linux) libio. it must be linked with several libraries. nextarg = 1.Compiling Code with the Mesh and Results Export API } else { /* need an argument */ if (!*place) { if (++argind >= argc) { fprintf (stderr.lib (on Windows).a (on UNIX/Linux) bufferoverflowu. argopt). or libio. The customized executable must also be linked with the provided Mesh and Results Export API library and the provided i/o library as detailed in Linking Code with the Mesh and Results Export API (p. or libratlas. Inc. or libratlas_api. 50). or libmeshexport.lib (on Windows).lib (on Windows). Compiler Flags The following compiler flags are necessary for successful compilation on the listed platforms: Platform hpux (pa-2) hpux-ia64 linux (32 bit) linux-ia64 solaris aix Flag +DS2.a (on UNIX/Linux) libratlas_api.© 2009 ANSYS.0W +DD64 <none> <none>. these libraries are located in <CFXROOT>/lib/<os>/: • • • • • • • • libmeshexport. or libpgtapi.a (on UNIX/Linux) libunits.lib (on Windows 64–bit) Release 12. All rights reserved. "missing argument for option `%c'\n". or libcclapilt.a (on UNIX/Linux) libratlas. or libunits. exit (1). /* return option letter */ } Compiling Code with the Mesh and Results Export API Compilation of a customized executable must be performed using an appropriate compiler and compiler flags. and its subsidiaries and affiliates.lib libio. depending on the compiler and the custom program. 54) Node Routines (p. 55) Element Routines (p.lib libpgtapi.lib bufferoverflowu.lib libmeshexport.c -o export. data structures. 57) Face Routines (p. 60) Boundary Condition Routines (p. In this example.lib libratlas_api. Contains proprietary and confidential information of ANSYS. linux.exe -I<CFXROOT>/include/ -L<CFXROOT>/lib/<OSDIR> -lmeshexpor where <CFXROOT> is the directory in which CFX is installed and <OSDIR> is a directory name corresponding to the architecture of the machine that you are running on (that is.lib libunits. types and functions available to the programmer are given in the following sections: • • • • • • • • • • Defined Constants and Structures (p. 62) Defined Constants and Structures The following constants and data structures are defined in the header file cfxExport. 61) Variable Routines (p. 53) Zone Routines (p. Release 12. Inc.lib libratlas. hpux-ia64.lib libpgtapi. 59) Volume Routines (p. An example command line follows: cl /MD /I “C:\Program Files\Ansys Inc\v121\CFX\include” ExportTemplate. Inc.lib Details of the Mesh Export API The full list of constants.1 .lib libratlas. 51) Initialization and Error Routines (p. build the executable with the command: cc export. hpux.© 2009 ANSYS.c /link /libpath:"C:\Program Files\Ansys Inc\v121\CFX\lib\winnt" libcclapilt. Windows (32-bit) You can build the executables on 32-bit Windows systems that have Microsoft Visual C++ 2005 Express Edition.exe. your own export program is named export. All rights reserved. one of solaris. which should be included in the export program.c /link /libpath:”C:\Program Files\Ansys Inc\v121\CFX\lib\winnt-amd64” libcclapilt. 56) Region Routines (p.UNIX UNIX On most UNIX systems. An example command line follows: cl /MD /I "C:\Program Files\Ansys Inc\v121\CFX\include" ExportTemplate.lib Windows (64-bit) You can build the executables on 64-bit Windows systems that have Windows Server 2003 Platform SDK.lib libratlas_api. aix.lib libunits. or linux-ia64).lib libio. 51 .lib libmeshexport.c and the executable file will be called export. The compiler flags and required libraries may vary.h. see Volume Routines (p. Inc. The following macros are available to enable the user to extract the element and face number from the combined value: #define cfxFACENUM(face) ((face) & 7) #define cfxELEMNUM(face) ((face) >> 3) Count Entries Two routines exist for initializing the Export API (see cfxExportInit (p. /* number of nodes */ cfxCNT_ELEMENT. All rights reserved. /* number of elements */ cfxCNT_VOLUME. /* number of hexahedral elements */ cfxCNT_SIZE /* size of count array */ }. the returned value is a combination of the global element number and local face number of the element. 60). /* number of wedge elements */ cfxCNT_HEX. see Region Routines (p. the global node number is returned.) The following constants are defined in the header file and should be used as arguments to the Volume routines: #define cfxVOL_NODES 0 #define cfxVOL_ELEMS 1 Region List Types The Export API contains functions that enable the user to query how regions are defined in the results file. enum cfxCounts { cfxCNT_NODE = 0. pyramids (5 nodes). /* number of tetrahedral elements */ cfxCNT_PYR.) The following constants are defined in the header file and should be used as arguments to the Region routines: #define cfxREG_NODES 0 #define cfxREG_FACES 1 In the case of nodes. /* number of regions */ cfxCNT_VARIABLE. /* number of variables */ cfxCNT_TET. It is possible to request how a volume is defined in terms of nodes or elements. and hexahedrons (8 nodes). which are identified by the number of nodes: tetrahedrons (4 nodes). and its subsidiaries and affiliates. 54)). 52 Contains proprietary and confidential information of ANSYS. The array returned from both of these routines requires the following constants to be used by the calling program to reference the correct quantities. 53)) and requesting the totals of certain quantities in a zone (see cfxExportZoneSet (p. . Inc. The element types are identified in the Export API by the following constants: #define #define #define #define cfxELEM_TET cfxELEM_PYR cfxELEM_WDG cfxELEM_HEX 4 5 6 8 Volume List Types The Export API contains functions that enable the user to query how volumes are defined in the results file. while in the case of faces. (For details. y and z): Release 12. It is possible to request how a region is defined in terms of nodes or faces. Node Data Structure Nodes are represented in the Export API using the following structure (note the change in data type of x. /* number of pyramid elements */ cfxCNT_WDG. 57). prisms/wedges (6 nodes).1 .Defined Constants and Structures Element Types CFX can use 4 types of element.© 2009 ANSYS. /* number of volumes */ cfxCNT_REGION. (For details. Initialization and Error Routines typedef struct cfxNode { float x. The argument. Contains proprietary and confidential information of ANSYS. Inc. the array is filled with values representing the total number of nodes. This should be the final call made to the Export API. If the array counts is supplied to the routine (that is. elements. 14)). cfxExportError void cfxExportError (void (*callback) (char *errmsg)) Specify a callback function that will be executed when a fatal error is generated by a call to cfxImportFatal (see cfxImportFatal (p. int counts[cfxCNT_SIZE]) Opens the CFX results file named resfile and initializes the Export API. 53) cfxExportDone (p. A pointer to an array of these structures is returned by cfxExportElementList. Inc. it should take an argument that is the error message passed to cfxImportFatal. The routine returns the total number of zones. cfxExportInit int cfxExportInit (char *resfile. It is the responsibility of the function to terminate the application if required. and z are the coordinates of the node. All rights reserved. 55). is the function that will be called. Element Data Structure Elements are represented by the Export API using the following structure: typedef struct cfxElement { int type. and handle fatal error processing. where x. 52) and cfxExportElementList (p. and its subsidiaries and affiliates. volumes. For details. } cfxElement. The first call to any of the API routines must be cfxExportInit and the last call should be cfxExportDone. callback. Initialization and Error Routines The following routines open and close the CFX results file. A pointer to an array of these structures is returned by cfxExportNodeList. y. 53 . This should be the first call made to the API. For details. } cfxNode. y.© 2009 ANSYS. it is not NULL). where type is the element type and nodeid is an array of node numbers that define the topology of the element.1 . regions and variables for all the zones are returned in this array. z. Release 12. initialize the Export API. see Element Types (p. int *nodeid. 56). see cfxExportNodeList (p. cfxExportDone void cfxExportDone () Closes the CFX results file and destroys any internal storage used by the API. see: • • cfxExportInit (p. For details. 53). In the case when counts is supplied correctly the total number of nodes. Inc. cfxExportZoneCount int cfxExportZoneCount () Return the number of zones in the CFX results file. The value of zone should be between 1 and the value returned by cfxExportZoneCount (see cfxExportZoneCount (p. cfxExportElementFree. All other routines in the Export API refer to quantities in the current zone being accessed by the API. elements. 54)) or 0 if the global zone is to be accessed. int counts[cfxCNT_SIZE]) Set the current zone being accessed by the Export API. this storage should be deallocated when no longer required. Inc. cfxExportVolumeFree. By default the current zone is the global zone (a combination of all zones in the ANSYS CFX results file). internal storage is allocated. If no callback function has been specified the function also terminates the application. not specifying an array large enough can result in errors. and its subsidiaries and affiliates. volumes. There is no return from this call. cfxExportZoneSet int cfxExportZoneSet (int zone. if one has been specified by cfxExportError (see cfxExportError (p. any other function returns information about this zone until a subsequent call is made. .Zone Routines cfxExportFatal void cfxExportFatal (char *errmsg) Generate a fatal error message (errmsg) and close the ANSYS CFX results file. 58) Release 12. but this can be the current zone can be altered by making a call to cfxExportZoneSet (see cfxExportZoneSet (p. The function returns 0 if the value of zone is invalid or the value zone if setting of the zone was successful. 61) cfxExportRegionFree (p.1 . regions and variables will be returned. 54 Contains proprietary and confidential information of ANSYS. Zone Routines A zone is defined as groups of nodes or faces that are located on the external boundaries of the domain. 54)). Once this call has been made. 56) cfxExportElementFree (p. In this case no information is returned to the calling function other than the return value mentioned above. 53)). This routine also calls a callback function. The following routines provide functionality for returning the number of zones in the open CFX results file specifying and requesting the current zone. This can be done by calling cfxExportZoneFree or by calling cfxExportNodeFree. Details on each of these routines is available. cfxExportZoneFree void cfxExportZoneFree () While a zone is being accessed. and destroying any internal storage associated with a zone. cfxExportZoneGet int cfxExportZoneGet () Returns the current zone number. 57) cfxExportVolumeFree (p. If counts is specified it must be at least cfxCNT_SIZE in size. cfxExportRegionFree and cfxExportVariableFree. All rights reserved.© 2009 ANSYS. The argument counts can be passed as a NULL pointer. see: • • • • cfxExportNodeFree (p. 21)) containing the coordinate values of each node in the current zone. double *y. Contains proprietary and confidential information of ANSYS. This reduces memory overheads in the API by not allocating space until required. a call to cfxExportNodeFree (see cfxExportNodeFree (p.Node Routines • cfxExportVariableFree (p. flag should be set to cfxMOTION_USE. If zone is not valid or flag is not cfxMOTION_USE. const int flag) Specify whether grid coordinates and variables should have the appropriate rotation applied to them if the zone is rotating so that grid coordinates appear in their correct locations and velocities (for examples) take this rotation into consideration.Returns 1 if the current zone is rotating and 0 if it is not. The first node in the zone is the first element of the array. The index (nodeid) is specified between 1 and the number of nodes returned by cfxExportNodeCount (see cfxExportNodeCount (p. If successful the rotation axis is returned in rotationAxis and the velocity in angularVelocity in radians/second. If the value of nodeid is out of range the return value is 0 otherwise it is nodeid. Inc. 55 . cfxExportNodeCount int cfxExportNodeCount () Query the number of nodes defined in the current zone. It should be noted that the nodes for a zone are not loaded into the Export API until either cfxExportNodeList (see cfxExportNodeList (p. double *z) Query the coordinates of a specific node in the current zone. for the combined zone the return value is always -1. The memory allocated to represent this information should be deallocated using cfxExportNodeFree (see cfxExportNodeFree (p. 56)) should be made to deallocate any internal storage. cfxMOTION_IGNORE the return value will be -1 otherwise 0 is returned. Inc.1 . and its subsidiaries and affiliates. cfxExportZoneMotionAction int cfxExportZoneMotionAction(const int zone. cfxExportZoneIsRotating int cfxExportZoneIsRotating(double rotationAxis[2][3]. cfxExportNodeList cfxNode *cfxExportNodeList () Return a pointer to an array of cfxNode elements (see cfxnode (p. When access to nodes in the current zone is no longer required. 55)) are called.If cfxExportZoneList and cfxExportVariableList should return rotated values. Release 12. Node Routines Accessing nodes within the current zone (see cfxExportZoneSet (p.© 2009 ANSYS. 64). the second the second and so on. 55)) or cfxExportNodeGet (see cfxExportNodeGet (p. 55)). 56)) when no longer required. 54)) is performed by making calls to the following functions. cfxExportNodeGet int cfxExportNodeGet (int nodeid. The default behavior for a particular zone will be used if cfxMOTION_IGNORE is specified or this function isn't called. double *x. All rights reserved. double *angularVelocity) Query whether the current zone is rotating and describe axis and angular velocity of the rotation if applicable. Inc. 57)) when no longer required. When access to elements in the current zone is no longer required a call to cfxExportElementFree (see cfxExportElementFree (p. the second the second and so on. 55)) and cfxExportNodeGet (see cfxExportNodeGet (p. Element Routines Accessing elements within the current zone (see cfxExportZoneSet (p.© 2009 ANSYS. The first element in the zone is the first element of the array.Element Routines cfxExportNodeFree void cfxExportNodeFree () Deallocate any internal storage allocated by the Export API after calls to cfxExportNodeList (see cfxExportNodeList (p. This reduces memory overheads in the API by not allocating space until required. cfxExportElementCount int cfxExportElementCount () Query the number of elements defined in the current zone. 56)) or cfxExportElementGet (see cfxExportElementGet (p. The memory allocated to represent this information should be deallocated using cfxExportElementFree (see cfxExportElementFree (p. It should be noted that the elements for a zone are not loaded into the Export API until either cfxExportElementList (see cfxExportElementList (p. 57)) should be made to deallocate any internal storage. and its subsidiaries and affiliates.1 . 54)) is performed by making calls to the following functions. 56 Contains proprietary and confidential information of ANSYS. Inc. 55)) have been made in the current zone. All rights reserved. 22)) containing the type and vertices of each element in the current zone. . The following diagrams show the order of the nodes and connections that ANSYS CFX uses for exporting elements: Release 12. 57)) are called. cfxExportElementList cfxElement *cfxExportElementList () Return a pointer to an array of cfxElement elements (see cfxelem (p. cfxExportElementFree void cfxExportElementFree () Deallocates any internal storage allocated by making calls to cfxExportElementList (see cfxExportElementList (p. All rights reserved. The index (elemid) is specified between 1 and the number of elements returned by cfxExportElementCount (see cfxExportElementCount (p. int elemtype. If the value of elemid is out of range the return value is 0 otherwise it is elemid. Contains proprietary and confidential information of ANSYS. For details. Accessing regions within the current zone (see cfxExportZoneSet (p.1 . Region Routines Regions are groups of faces in an ANSYS CFX results file. It should be noted that the region information is not loaded into the Export API until either cfxExportRegionList (see cfxExportRegionList (p. and its subsidiaries and affiliates. Inc. 58)) or cfxExportRegionGet (see cfxExportRegionGet (p. 57 . 56)). 56)) or cfxExportElementGet (see cfxExportElementGet (p.© 2009 ANSYS. int *nodelist) Query the type and vertices of a specific element in the current zone. 57)). see cfxImportElement (p. Note that nodelist must be large enough to hold the element number of vertices in the element (normally an array of 8 integers is used as this allows space enough for all element types to be handled).Region Routines Note The vertex ordering for the import API is different. Inc. 15). 58)) are called. This reduces memory overheads in the API by not allocating space until required. cfxExportElementGet int cfxExportElementGet (int elemid. Release 12. The type of the element is returned in elemtype and the vertices defining the element in nodelist. 54)) is performed by making calls to the following functions. cfxExportRegionList int *cfxExportRegionList (int regnum. cfxExportRegionName char *cfxExportRegionName (int regnum) Query the name of the region in the current zone identifies by regnum. cfxExportRegionGet int cfxExportRegionGet (int regnum. If regnum is out of range or type is not recognized or index is out of range. This function returns a pointer to an array of node ids or face ids that define the region identified by regnum or NULL if the region number is out of range or the type is not recognized. 58)) should be made to deallocate any internal storage. cfxExportRegionCount int cfxExportRegionCount () Query the number of regions defined in the current zone. 58 Contains proprietary and confidential information of ANSYS. Otherwise id will contain the id of the appropriate node or face defining the region and the function will return index. int index. Inc. int *id) Query the index'th element (type is cfxREG_ELEM) or index'th node (type is cfxREG_NODE) that defines a the region regnum in the current zone.1 . the returned ids will represent faces. The node numbers for the face may be obtained by calling cfxExportFaceNodes. int type. All rights reserved. int type) Query the number of faces (if type is cfxREG_FACES) or nodes (if type is cfxREG_NODES) defined in the region identified by regnum in the current zone. 0 is returned. cfxExportRegionFree void cfxExportRegionFree (int regnum) Deallocate any internal data storage associated with the region defined by regnum. Inc. The function returns the name of the region or NULL if the region number supplied is out of range. The pointer returned points to static storage. and its subsidiaries and affiliates. The element number and local element face number may be extracted from the id by using the macros cfxELEMNUM and cfxFACENUM. 59). see cfxExportFaceNodes (p. the returned id will represent the identity of a face. which will be overwritten by the next call to cfxExportRegionName. Release 12. For details. The element number and local element face number may be extracted from each face id returned by using the macros cfxELEMNUM and cfxFACENUM. . The function returns the number of faces or nodes in the current zone or 0 if either regnum is out of range or type is invalid. If type is specified as cfxREG_FACES.Region Routines When access to region in the current zone is no longer required a call to cfxExportRegionFree (see cfxExportRegionFree (p.© 2009 ANSYS. If type is specified as cfxREG_FACES. cfxExportRegionSize int cfxExportRegionSize (int regnum. int type) Query the nodes (type is cfxREG_NODES) or faces (cfxREG_FACES) that define a region. Inc. 62)) or cfxExportRegionList (see cfxExportRegionList (p. Contains proprietary and confidential information of ANSYS. Within CFX faces are either represented as Triangles (three vertices) or Quadrilaterals (two vertices). 58)).Face Routines Face Routines Faces are 2 dimensional (2D) units of mesh. The node numbers are returned in the array nodes.res file will be parented by a single 3D element.1 . Each global face ID is returned from cfxExportBoundaryList (see cfxExportBoundaryList (p. and its subsidiaries and affiliates. int *nodes) Requests the vertices for the face identified by faceid. which should be dimensioned to a minimum size of 4 in the calling routine. 59 . The parent element of a face can be returned by the cfxELEMNUM macro with the global face ID.© 2009 ANSYS. The number of vertices defining the face are returned if faceid is valid. Inc. The argument faceid should be constructed from the element number and local face number using the following formula: (element_number << 3) & local_face_number Values returned from cfxExportRegionGet and cfxExportRegionList can be supplied directly to this function. The face numbers and associated node indices are tabulated here: Element Type tetrahedron Face 1 2 3 4 pyramid 1 2 3 4 5 prism 1 2 3 4 5 hexahedron 1 2 3 4 5 Nodes 0 0 1 0 0 1 0 2 0 0 0 1 0 3 0 1 0 2 0 1 3 3 2 3 4 4 4 1 2 3 4 1 5 2 5 4 3 1 2 1 2 3 4 2 1 3 2 5 4 5 2 4 6 7 5 7 3 4 3 1 6 2 3 3 1 2 Release 12. and the local face of that element can be determined by calling cfxFACENUM with the same global face ID cfxExportFaceNodes int cfxExportFaceNodes (int faceid. All rights reserved. Each face in a CFX . otherwise 0 is returned. . Inc. Inc. Volume Routines Volumes are groups of elements in an CFX results file. cfxExportVolumeCount int cfxExportVolumeCount () Query the number of volumes defined in the current zone. For details. This reduces memory overheads in the API by not allocating space until required. Returns NULL if the volnum is out of range.1 . 60 Contains proprietary and confidential information of ANSYS. Release 12. int type) Query the number of nodes (if type is cfxVOL_NODES) or number of elements (if type is cfxVOL_ELEMS) defining the volume indexed by volnum in the current zone. All rights reserved. Note The returned pointer points to internal storage. and its subsidiaries and affiliates. Accessing volumes within the current zone (see cfxExportZoneSet (p. 17). 61)) should be made to deallocate any internal storage.© 2009 ANSYS. This function returns a pointer to an array of node ids or element ids that define the volume identified by volnum or NULL if the volume number is out of range or the type is not recognized. When access to volume information in the current zone is no longer required a call to cfxExportVolumeFree (see cfxExportVolumeFree (p. It should be noted that the volume definitions for a zone are not loaded into the Export API until either cfxExportVolumeList (see cfxExportVolumeList (p. cfxExportVolumeName char *cfxExportVolumeName (int volnum) Query the name of the volume in the current zone indexed by volnum. 61)) are called. cfxExportVolumeSize int cfxExportVolumeSize (int volnum. cfxExportVolumeList int *cfxExportVolumeList (int volnum.Volume Routines Element Type Face 6 Nodes 4 6 7 5 Note The face numbers and associated node indices are different when importing elements. The return value will be 0 if volnum is out of range or type is invalid. 54)) is performed by making calls to the following functions. which will be overwritten by the next call to cfxExportVolumeName. int type) Query the nodes (type is cfxVOL_NODES) or elements (cfxVOL_ELEMS) that define a volume. see cfxImportGetFace (p. 60)) or cfxExportVolumeGet (see cfxExportVolumeGet (p. The function returns the type of the boundary condition or NULL if the bcidx supplied is out of range. Inc.Boundary Condition Routines cfxExportVolumeGet int cfxExportVolumeGet (int volnum.) of the boundary condition in the current zone identified by bcidx. The function returns the name of the boundary condition or NULL if the bcidx supplied is out of range.© 2009 ANSYS. int type. The pointer returned points to static storage. The function returns the number of boundary conditions in the current zone. int index. cfxExportBoundaryName const char *cfxExportBoundaryName (const int bcidx) Query the name of the boundary condition in the current zone identified by bcidx. Boundary Condition Routines Boundary condition are located on groups of faces in an CFX results file. 0 is returned. Inlet. When access to regions in the current zone are no longer required a call to cfxExportBoundaryFree (see cfxExportBoundaryFree (p. 62)) are called. 62)) or cfxExportBoundaryGet (see cfxExportBoundaryGet (p. 54)) is performed by making calls to the following functions. 61 . It should be noted that the boundary condition location information is not loaded into the Export API until either cfxExportBoundaryList (see cfxExportBoundaryList (p. int *id) Query the [index]th element (type is cfxVOL_ELEM) or [index]th node (type is cfxVOL_NODE) that defines a the volume volnum in the current zone. Note The following routines use bcidx which must lie between 1 and cfxExportBoundaryCount() and use index which must lie between 1 and cfxExportBoundarySize (bcidx. All rights reserved. cfxExportBoundaryCount int cfxExportBoundaryCount () Query the number of boundary conditions defined in the current zone. Contains proprietary and confidential information of ANSYS.1 . The pointer returned points to static storage. Outlet etc. Accessing boundary condition locations within the current zone (see cfxExportZoneSet (p. which will be overwritten by the next call to cfxExportBoundaryType. cfxExportVolumeFree void cfxExportVolumeFree (int volnum) Deallocate any internal data storage associated with the volume defined by volnum. If volnum is out of range or type is not recognized or index is out of range. type). Inc. and its subsidiaries and affiliates. Otherwise id will contain the id of the appropriate node or element in defining the volume and the function will return index. 62)) should be made to deallocate any internal storage. This reduces memory overheads in the API by not allocating space until required. cfxExportBoundaryType const char *cfxExportBoundaryType (const int bcidx) Query the type (for example. which will be overwritten by the next call to cfxExportBoundaryName. Release 12. see: • • • cfxExportVariableList (p. If type is specified as cfxREG_FACES. For details. The returned pointer points to static data which should be destroyed using cfxExportBoundaryFree. see cfxExportZoneSet (p. . the returned ids will represent faces. const int type. The node numbers for the face may be obtained by calling cfxExportFaceNodes. const int type) Query the faces (if type is cfxREG_FACES) or nodes (if type is cfxREG_NODES) that define a boundary condition. 63) cfxExportVariableGet (p. Subsequent calls to cfxExportBoundaryList will overwrite the array. If bcidx is out of range or type is not recognized or index is out of range (not between 1 and cfxExportBoundarySize). 63) cfxExportVariableFree (p. 0 is returned. Release 12. 54). The element number and local element face number may be extracted from the id by using the macros cfxELEMNUM and cfxFACENUM respectively. The variable data arrays are not loaded into memory until either cfxExportVariableList or cfxExportVariableGet are called.© 2009 ANSYS. int *id) Query the index'th face (type is cfxREG_FACES) or index'th node (type is cfxREG_NODES) that defines the boundary condition location indexed by bcidx in the current zone. The element number and local element face number may be extracted from each face id returned by using the macros cfxELEMNUM and cfxFACENUM respectively. All rights reserved. cfxExportBoundaryList int *cfxExportBoundaryList (const int bcidx. 62 Contains proprietary and confidential information of ANSYS. const int type) Query the number of faces (if type is cfxREG_FACES) or nodes (if type is cfxREG_NODES) defined in the boundary condition identified by bcidx in the current zone. Inc. For details. see cfxExportFaceNodes (p. 64). cfxExportBoundaryGet int cfxExportBoundaryGet (const int bcidx. This function returns a pointer to an array of node ids or face ids that define the location of the boundary condition identified by bcidx or NULL if bcidx is out of range or the type is not recognized. then the total number of variables is returned.Variable Routines cfxExportBoundarySize int cfxExportBoundarySize (const int bcidx.1 . For details. cfxExportBoundaryFree void cfxExportBoundaryFree (const int bcidx) Deallocate any internal data storage associated with the boundary condition defined by bcidx. and remain in memory until cfxExportVariableFree is called. const int index.If type is specified as cfxREG_FACES. and its subsidiaries and affiliates. The function returns the number of faces or nodes or 0 if either bcidx is out of range or type is invalid. the returned id will represent the identity of a face. Inc. Variable Routines These routines access the variable data defined on the current zone as defined by cfxExportZoneSet. cfxExportVariableCount int cfxExportVariableCount(int usr_level) Query the number of variables at interest level usr_level or below. Otherwise id will contain the identifier of the appropriate node or face defining the boundary condition location and the function will return index. If usr_level is 0. 59). cfxExportVariableName char *cfxExportVariableName (int varnum. The pointer returned points to static storage. the short and long names for the total temperature variable are TEMPTOT and Total Temperature. then the variable has meaningful values only at the boundary nodes. dimension. int correct. int *bdnflag) Query the dimension. cfxExportVariableGet int cfxExportVariableGet (int varnum.Variable Routines cfxExportVariableSize int cfxExportVariableSize (int varnum. which will be overwritten by the next call to cfxExportVariableName. cfxExportVariableList float *cfxExportVariableList (int varnum. The function returns varnum if successful. and its subsidiaries and affiliates. or 0 if the variable number is out of range. which should be from 1 to the number of variables. which should be from 1 to the length of the variable. Returns NULL if the variable number is out of range or the variable data if successful. All rights reserved. 55)). length. The length. Contains proprietary and confidential information of ANSYS. For example. the data is stored with dimension consecutive values for each node. assuming that it exists. and length. with a constant value in the interior. will either be 1 or the same as the number of nodes returned by cfxExportNodeCount (see cfxExportNodeCount (p. for the variable identified by varnum. respectively. inclusively. int *dimension. Inc. The storage for the data is created by the Export API when this function is called. If 1. length. The flag correct indicates whether to correct boundary node data (correct=1) or not (correct=0). The return value of the function is NULL if the variable number is out of range or the name of the variable. int *length.1 . 63 . int correct) Query the results data for a variable identified by varnum. 62)). float *value) Request the values of the variable identified by varnum at the location given by index. The function also returns bdnflag which indicates if the variable contains corrected boundary node values (1) or not (0). assuming that it exists. returned by cfxExportVariableCount (cfxExportVariableCount (p. Inc. The values of the variable are returned in value which should be dimensioned at least as large as the dimension of the variable. 55)). 64)) should be made by the calling function. or 0 if the location is out of range. The function returns index. int index. The flag correct indicates whether to correct boundary node data (correct=1) or not (correct=0). For multidimensional variables. When the data is no longer required a call to cfxExportVariableFree (see cfxExportVariableFree (p. The argument alias indicates whether the short name (alias=0) or long name (alias=1) should be returned. The data is in the same order as the nodes returned from cfxExportNodeList (see cfxExportNodeList (p. int alias) Query the name of the variable identified by varnum.© 2009 ANSYS. Release 12. Variable Routines cfxExportVariableFree void cfxExportVariableFree (int varnum) Deallocates the internal data storage for the variable identified by varnum for the current zone. Inc. . All rights reserved. 64 Contains proprietary and confidential information of ANSYS.1 .© 2009 ANSYS. Inc. Release 12. and its subsidiaries and affiliates. Chapter 4. As described in Remeshing Tab (p. the Preprocessing and Solution steps (and their respective sub-steps) are automatically executed for both remeshing options. Remeshing Guide Periodic remeshing is an important part of running analyses that involve significant mesh deformation.© 2009 ANSYS. Figure 4. the highlighted steps are responsible for the completing the following sub-steps. Preprocessing: Insert the new mesh(es) into the analysis definition. Inc. Solution: Interpolate the previously generated analysis results onto the new mesh. Remeshing is often required simply to maintain acceptable mesh quality. Contains proprietary and confidential information of ANSYS. in addition to the Preprocessing and Solution steps of the standard simulation workflow. • • • • • Data Extraction: Extract any data needed to guide geometry modifications and mesh re-creation from the most recent analysis results and monitor point values. there are two options available for remeshing: User Defined and ICEM CFD Replay. 255) in the ANSYS CFX-Solver Theory Guide and Measures of Mesh Quality (p. Although the remaining steps are automatically executed for the ICEM CFD Replay remeshing option. the remeshing loop includes three additional steps: Data Extraction. As outlined in the discussions that follow. Geometry Modification and Mesh Recreation. and continue the solution process. 65 . Mesh Re-Creation: Generate new mesh(es) that correspond to the updated geometry. re-partition the mesh if a parallel run mode is selected. A schematic illustrating the integration of remeshing into the general simulation workflow is shown in the figure below. 224) in the ANSYS CFX-Pre User's Guide. Release 12.1 . Inc. All rights reserved. and its subsidiaries and affiliates. Integration of remeshing loop into general simulation workflow As shown in the figure. account for mesh deformation). as described in Discretization Errors (p. and generate an updated CFX-Solver Input File.1. Geometry Re-Creation: Update the analysis’ geometry so that it conforms to that of the most recent analysis results (that is. In the context of remeshing. 324) in the ANSYS CFX-Solver Modeling Guide. they become the responsibility of a user defined external command for the User Defined remeshing option. the iteration or time step number at which unacceptable mesh quality will occur due to mesh motion is also known. When this option is used. . the motion of various boundaries and sub-domains is known apriori. and its subsidiaries and affiliates. Thus. as illustrated in the figure below where the dashed line identifies steps that must be executed by the user-specified External Command.© 2009 ANSYS. Figure 4. Schematic for User Defined remeshing This remeshing option is ideally suited for users that have previously completed an ‘in-house’ remeshing solution involving scripts or varying degrees of manual user-intervention. A configuration is subsequently defined (unless this has already been done). they should be placed in a location that will be accessible during the analysis’ execution.2. re-partition the mesh if a parallel run mode is selected. and continue the solution process.1 . Inc. and geometry and mesh re-creation steps are executed by a user specified external command. and a remeshing definition is created with the following settings: Release 12. All rights reserved. A sequence of ‘key-frame’ meshes (of any mesh file type) corresponding to these instances of poor mesh quality can consequently be generated and applied during the analysis. This comes at the expense of requiring that the data extraction. the following steps are automatically executed: • • • run the specified external command to generate a new mesh(es) insert the new mesh(es) into the analysis definition. and generate an updated CFX-Solver Input file interpolate the previously generated analysis results onto the new mesh.User Defined Remeshing User Defined Remeshing User Defined remeshing offers the greatest flexibility to customize the remeshing process. Once the sequence of key-frame meshes has been generated. The analysis definition is then modified to include one or more control conditions that will interrupt the solver at the iteration or time step at which a key-frame mesh should be inserted. 66 Contains proprietary and confidential information of ANSYS. Remeshing with Key-Frame Meshes Remeshing with Automatic Geometry Extraction The following examples outline the use of the User Defined remeshing option: • • Remeshing with Key-Frame Meshes In some analyses involving mesh deformation. Inc. Output generated from the cfx5mondata executable can also be parsed instead of the run’s output file. geometrical information must be extracted from the most recent analysis results and applied in the remeshing process. Extract geometry data from the most recent solution of the analysis. In these analyses. In such cases. and its subsidiaries and affiliates. Unless otherwise noted. then introduce a call to CFX-Pre (within the External Command) that executes a session file that simply loads the latest CFX-Solver Results file and writes a new CFX-Solver Input file. and either update or replace the original geometry. latest mesh coordinates.Remeshing with Automatic Geometry Extraction • • • • • • Set Option to User Defined. and a remeshing definition is created with the following settings: • • • • • • Set Option to User Defined. Inc. Determine which key-frame mesh to use. The External Command is typically a shell script or batch file that completes the following tasks: • Note that some mesh-to-geometry conversion tools are unable to extract the latest mesh coordinates from the most recent CFX-Solver Results file. for example. or by extracting monitor point data values (for example. 67 . along with the general process flow for this remeshing option. 3) in the ANSYS CFX-Solver Manager User's Guide.e. A configuration is subsequently defined (unless this has already been done). Contains proprietary and confidential information of ANSYS. Inc. Copy the key-frame mesh to the path the specified by the Replacement File setting. When this option is used. the motion of various boundaries and sub-domains is not known a-priori and the key-frame remeshing strategy presented above is not applicable. Release 12. For details. see Exporting Monitor Data from the Command Line (p. That CFX-Solver Input file will contain the required. or the actual simulation time. the Total Centroid Displacement variable) using the cfx5mondata executable. The dashed line in the figure highlights components of the master replay file and identifies files and steps that can be modified by the user. All rights reserved. files are contained in the <CFXROOT>/etc/Remeshing directory. the analysis definition is modified to include one or more control conditions that will interrupt the solver when. This will require parsing the run’s output file for the iteration or time step number. Create a replacement mesh file using the updated or newly generated geometry. a master replay file is assembled from other task-oriented replay files and submitted to the ANSYS ICEM CFD mesh generator for batch execution. ICEM CFD Replay Remeshing ICEM CFD Replay remeshing provides a highly automated remeshing process that is ideally suited for users of the ANSYS ICEM CFD mesh generation software and cases that involve translational mesh motion only (i. Set the Replacement File to the name of the file that will be generated by the external command. For details. Set the External Command to the command that will be used to generate the replacement mesh file. 3) in the ANSYS CFX-Solver Manager User's Guide. Set the Activation Condition(s) to the previously created interrupt control condition(s). Set the Replacement File to the name of the file that will be generated by the external command. Set the Activation Condition(s) to the previously created interrupt control condition(s). This may be done using mesh-to-geometry conversion tools available in software such as ANSYS ICEM CFD. Set the Location to the mesh region that will be replaced.1 . Set the External Command to the command that will be used to generate the replacement mesh file.© 2009 ANSYS. If this is the case. mesh quality deteriorates significantly. Set the Location to the mesh region that will be replaced. no rotation or general deformation). This may be done in any suitable mesh generation application. These replay files are illustrated in the figure below. see Exporting Monitor Data from the Command Line (p. The External Command is typically a shell script or batch file that completes the following tasks: • Remeshing with Automatic Geometry Extraction In some analyses involving mesh deformation. Inc. and generate an updated CFX-Solver Input file. specified in the Remesh definition. 68 Contains proprietary and confidential information of ANSYS. or using the user defined replay file if specified in the ICEM CFD Geometry Control setting. Release 12. These files may be edited to provide installation-wide changes to the ICEM CFD Replay remeshing behavior. or using the user defined replay file if specified in the ICEM CFD Mesh Control setting. The generic default replay files (icemcfd_Remesh. since these are specific to each case.ICEM CFD Replay Remeshing Figure 4. The reference Geometry File and the Mesh Replay File must be created by the user.rpl. Run (in batch) the ANSYS ICEM CFD mesh generation program using the master replay file. Inc. provided in the <CFXROOT>/etc/Remeshing directory. Load the user’s Mesh Replay File. This is done using the provided provided. however. re-partition the mesh if a parallel run mode is selected. Interpolate the previously generated analysis results onto the new mesh. Alternatively.© 2009 ANSYS. and continue the solution process. This is done using the provided controls. Apply ICEM CFD Mesh Controls defined in the Remesh definition. This master replay file executes the following tasks: • • • Read the cfx_params. the following steps are automatically executed: • Extract geometry and mesh control data and write them to the cfx_params. Apply displacements (including scaling and any offsets) corresponding to all ANSYS ICEM CFD Part Map definitions contained in the Remesh definition. and icemcfd_MeshMod.rpl) used by this option are. All rights reserved.rpl. the geometry and mesh modification files may be copied and edited to provide case-specific changes. Export a new mesh for ANSYS CFX.3. icemcfd_GeomMod. . Load the reference geometry from the Geometry File identified in the Remesh definition. and its subsidiaries and affiliates.rpl replay file in the run directory. These data include: • • • • Centroid displacements for boundaries that are included in ANSYS ICEM CFD Part Maps Mesh control parameters (for example.1 . • • • • • Insert the new mesh(es) into the analysis definition.rpl file. ehgt and emax) Scalar parameters. Schematic for ICEM CFD Replay remeshing When this option is used. store the geometry in the ICEM CFD native geometry file format (namely. Define expressions for the motion of the geometry (for example. This may require fine tuning. and its subsidiaries and affiliates. to identify the condition(s) under which solver execution will be interrupted. Once you are satisfied with the mesh control settings. only translational mesh motion is automatically handled by the ICEM CFD Replay remeshing option. The Replay Control dialog is displayed. 3. Complete the following tasks to generate the required Mesh Replay File: 1. Inc. 4. All other mesh motion (such as rotation about the centroid or another point. The Geometry File and Mesh Replay File created above are referenced here. clear the Record (after current) toggle and select Save to write the settings to replay file. Note See also the discussion in Mesh Re-Initialization During Remeshing (p. Steps to Set Up a Simulation Using ICEM CFD Replay Remeshing The following discussion presents the three general steps required to setup a simulation using the ICEM CFD Replay remeshing option. 2. Complete any execution controls for the simulation and either start the solver or write the CFX-Solver Input file for later use. Finally. You may also want to export the mesh that was (re)generated for use in the simulation definition (as in the next step).1 . see the expressions for the ball movement in Fluid Structure Interaction and Mesh Deformation (p. and work sequentially through the mesh generation process until acceptable mesh controls have been specified. The third step involves defining the simulation within CFX-Pre. from within the ANSYS ICEM CFD environment. purge the last mesh using File>Mesh>Close Mesh…. Note also. Complete the following tasks to prepare the simulation: 1. 3. . This is accomplished by applying the displacements of centroids of boundaries in the ANSYS CFX analysis definition to parts in the ANSYS ICEM CFD geometry. Use File>Replay Scripts>Replay Control to begin recording the commands for the Mesh Replay File. Generate the mesh. The second step involves generating the Mesh Replay File.Steps to Set Up a Simulation Using ICEM CFD Replay Remeshing Note As indicated previously. 2. 5. and an inconsistency in the analysis geometry before and after remeshing will be introduced.© 2009 ANSYS. At this point. Start with the previously created geometry loaded. which will involve re-generate your mesh after moving the geometry through its expected range of motion. Define the flow analysis including the definition of one or more solver interrupt controls. All rights reserved. Start a new simulation and import the (previously generated) mesh. Contains proprietary and confidential information of ANSYS. In the Replay Control panel. clicking either the Apply or OK to commit the settings into the Replay Control panel. ensure that all required Parts (or Families) are defined and named so that they can be referenced when completing the ICEM CFD Replay remeshing definition later in CFX-Pre. that references to one or more of the previously defined solver interrupt control conditions are required to activate remeshing. as described in Interrupt Control (p.tin file). a . Inc. or general deformation) will not be applied. again. 327) in the ANSYS CFX Tutorials). 226) in the ANSYS CFX-Pre User's Guide. Revisit all of the mesh related tabs and settings used to generate the mesh. 148) in the ANSYS CFX-Pre User's Guide. The first step involves creating the reference Geometry File within the ANSYS ICEM CFD environment. Use one of the File>Import Geometry options in the ANSYS ICEM CFD environment if the geometry was not created within that environment. 69 . 70). and reload the original reference geometry. Define a configuration and complete the ICEM CFD Replay remeshing setup as described inANSYS ICEM CFD Replay Remeshing (p. Release 12. 4. replaced or removed during the next instance of remeshing or when the analysis ends and the run directory is deleted. This can be used to evaluate the required offset for time varying mesh displacement. and its subsidiaries and affiliates. Just after inserting the new mesh(es) into the analysis definition. The second. The results file written by the solver still has the generic name.dir/ 3_full.res 3_remesh.out case_001. using a CFX-Solver input file named case.def case_001/ 1_full. Inc. case_001. For example. These files are. 71) Mesh Re-Initialization During Remeshing The following points are important to note during remeshing: • • • The total mesh displacement variable is relative to a specific mesh topology. is used by CFX-Pre to generate the updated the solver input file.trn 0_full. In this example. this variable is reset each time remeshing occurs.1 . The results and console output files are renamed (to 5_oldmesh. and monitor data (contained in the mon file) has not yet been inserted into the results file. all CFX-Solver Results files (such as transient. Release 12.trn 4_full. and remeshing) contained in the run directory. An example of the expressions used to evaluate an applied displacement that includes the required offset to account for mesh re-initialization is given below.res and 5_remesh. were moved into the final solution directory. Since the mesh topology changes. The results file written when the solver was interrupted before remeshing was renamed to 3_oldmesh.Directory Structure and Files Used During Remeshing Directory Structure and Files Used During Remeshing CFX-Solver runs that include remeshing will have a slightly non-standard directory structure during execution. 5_newmesh. The Mesh Initialisation Time variable corresponds to the time at which mesh re-initialization last occurred.def. Inc.trn 2_full. 70) Software License Handling (p. The new variable called total centroid displacement tracks the displacement of each boundary’s centroid since the beginning of the analysis (that is.pre. All rights reserved. the applied displacement is evaluated as the desired displacement minus the value of the desired displacement at the Mesh Initialisation Time. Additional Considerations This section discusses the following additional considerations for remeshing: • • Mesh Re-Initialization During Remeshing (p. An automatically generated session file. and currently running instance of remeshing began when the solver was interrupted after the fifth time step. . Following this instance of remeshing. backup. relative to the original mesh). res. a directory structure similar to the following will exist just after solution execution is interrupted and the second instance of remeshing begins: case.def. and each of these files are present in the run directory. case_001. The specified displacement based mesh motion is relative to the initial mesh and must therefore include an offset to account for mesh re-initialization.res. Any text output to the console window during remeshing was redirected to the file named 3_remesh. which is also placed in the final solution directory.dir. 70 Contains proprietary and confidential information of ANSYS.out.© 2009 ANSYS. meshUpdate. respectively) and moved from the run directory into the final solution directory. however.trn 3_oldmesh.trn res mon The first instance of remeshing occurred when the solver was interrupted after the third time step.out. the files contained in the final solution and run directories change slightly. CFX-Pre. it also introduces the possibility that required licenses are not available when they are needed for remeshing. Inc.5*(1-cos(2. the CFX-Solver. they are only ‘checked out’ as required.5*(1-cos(2. ANSYS ICEM CFD. 71 .[s^-1]*pi*Mesh Initialisation Time )) Disp Applied = Disp Desired .[s^-1]*pi*t)) Disp Mesh ReInit = 1[m]*0. and its subsidiaries and affiliates.Software License Handling Disp Desired = 1[m]*0. Inc.Disp Mesh ReInit Software License Handling Several software components (for example.1 . etc…) are used while executing steps in the overall remeshing process. Rather than holding all of these licenses for the entire duration of the analysis. Release 12. Although this frees up the licenses for other users when remeshing is not executing. and work is underway to provide a broader range of handling options for future releases.© 2009 ANSYS. This model for software license handling may cause problems in multi-user environments. All rights reserved. Contains proprietary and confidential information of ANSYS. Inc. All rights reserved.1 . Contains proprietary and confidential information of ANSYS. Inc.© 2009 ANSYS. and its subsidiaries and affiliates.Release 12. . In these cases. In general. this capability is available in fluid and solid domains. Fluid Structure Interaction is an excellent example of this. Consistency of Mesh Motion Specifications Mesh motion options such as Specified Displacement may be applied on multiple boundary and subdomain regions. External Coupling Tab (p. a message indicating the existence and location of either negative sector volumes or negative (that is. All rights reserved. Contains proprietary and confidential information of ANSYS. In CFX. Inc. then the motion applied to the shared nodes will be either the moving or stationary condition. 74) Mesh Deformation Mesh deformation is an important part of executing simulations with changing domain geometry.© 2009 ANSYS. Since the specified motion is applied directly to mesh nodes. which is a fatal condition Some of the most common causes for mesh folding during deformation are identified in the following sections. Applying Large Displacements Gradually In many simulations that require mesh deformation. the motion is known a priori. the desired total mesh deformation should be split up so that regions where motion is specified move through less than approximately 5 adjacent elements per step. For example. rather than control volume integration points. and its subsidiaries and affiliates.1 . This guide describes: • • Mesh Deformation (p. Folded meshes often result from the application of inconsistent motion specifications. Release 12. mechanisms available for under-relaxing the displacements applied per deformation step should be used. care is required to ensure that motion specified on adjacent regions is self-consistent. the motion is not known a priori. When this occurs. Mesh folding is often avoided with this strategy because the mesh displacement equations are assembled using the updated meshes from each deformation step (that is. Reference Guide for Mesh Deformation and Fluid-Structure Interaction This guide is part of a series that provides advice for using CFX in specific engineering application areas. it does indicate that: • • Mesh elements are only barely positive Further mesh deformation is likely to yield elements with negative volumes. 73 . Although the existence of negative sector volumes is not a fatal condition. the motion can be applied gradually. Inc. to reduce the likelihood of mesh folding. Notification of negative sector volumes highlights the existence of non-convex mesh elements that still have a positive volume. If this is not done. In some simulations. Mesh Folding: Negative Sector and Element Volumes It is not uncommon for the mesh to become folded (or tangled) during the mesh deformation process. Motion can be specified on selected regions via CEL or an external solver coupling (for example. outer iteration or timestep). It is aimed at users with little or moderate experience using CFX for applications involving Mesh Deformation and/or Fluid Structure Interaction. see Solver Controls. 73) Fluid Structure Interaction (p. For details. depending on which was applied last during the equation assembly process. ANSYS Multi-field MFX).Chapter 5. by relating it to the iteration or timestep counters. topologically invalid) elements is written to the simulation output file. or on all nodes in an entire domain via a user-Fortran junction box routine. In these cases. the motion specified on one moving wall should be reduced to zero for any nodes that are shared with another stationary wall. 302) in the ANSYS CFX-Solver Modeling Guide. and are changed by visiting the Mesh Displacement entry in the Equation Class Settings tab under Solver Control. Unlike other equation classes. the convergence level (that is. In this case. Mesh Displacement is the principal variable that is solved for by the mesh motion model (see Mesh Deformation (p. One example Release 12. The default convergence controls and criteria for the mesh displacement equation are tabulated below. Inc. or take part in the solution of cases that involve the coupling of solution fields in fluid and solid domains. With only the exception noted.1 . This coupling is commonly referred to as Fluid Structure Interaction (FSI). Mesh Displacement vs. 74 Contains proprietary and confidential information of ANSYS. turbulence. Total Mesh Displacement A number of new variables become available when executing simulations with mesh deformation. Inc. the unconverged displacement solution field does not vary smoothly enough to ensure that adjacent mesh nodes move by similar amounts. Setting Maximum Number of Coefficient Loops Minimum Number of Coefficient Loops Residual Type Residual Target Value 5 1 RMS 1. Folded meshes can occur if the displacement equations are incompletely solved. Fluid Structure Interaction CFX provides the ability to solve. the mesh displacement equations are solved to the specified convergence level and the resulting displacements are applied to update the mesh coordinates. All rights reserved.) equations. Simulation Restart Behavior The following table summarizes the behavior that occurs when simulations with (or without) mesh deformation are restarted with (or without) mesh deformation. This occurs before proceeding to solve the general transport (for example.Solving the Mesh Displacement Equations and Updating Mesh Coordinates Solving the Mesh Displacement Equations and Updating Mesh Coordinates During each outer iteration or timestep. This variable represents the displacement relative to the previous mesh locations. steady state or transient) used for the initial or restart run does not affect behavior. Initial Simulation No Deformation Deformation Deformation Restart Simulation Deformation No Deformation Deformation Restart Behavior Mesh from initial run serves as initial mesh for restart run Final mesh from initial run serves as mesh for restart run Initial mesh from initial run serves as initial mesh for restart runa a If the restart is a transient run with the initial time set to Value. and its subsidiaries and affiliates. hydrodynamics. etc.0E-4 Mesh folding occurs and is detected when the displacements are used to update the mesh coordinates. Total Mesh Displacement is a derived quantity that represents the displacement relative to the initial mesh. 3) in the ANSYS CFX-Solver Modeling Guide). . Conversely. then the final mesh from the initial run will serve as the initial mesh for the restart simulation.© 2009 ANSYS. controls and criteria) applied to mesh displacement equations is unaffected by changes made to the basic settings for all other equations. the simulation type (that is. Two of these variables are Mesh Displacement and Total Mesh Displacement. 3. from which you want to transfer results. importing the surface in CFD-Post. Export Data to Other ANSYS Software Products Two methods exist for exporting data from CFX for use in other ANSYS software products. Inc. refer to the Custom Systems discussion presented in the ANSYS Workbench help documentation. the capabilities of additional solvers are required to compliment those of CFX. refer to the Unidirectional Load Transfer discussion.1 . Using CFX and the Mechanical Application In many FSI simulations. Unidirectional (One-Way) FSI In many FSI simulations. either: • Select the CDB file that specifies the surface mesh of the solid object to which to transfer data. In the Import ANSYS CDB Surface dialog. Importing Data from the Mechanical Application Solver The recommended method for importing boundary condition data from the Mechanical application into CFX is via boundary profile data. These examples are grouped according to the degree of coupling that must be maintained during the simulation in order to ensure that accurate results are obtained. 113) in the ANSYS CFX-Pre User's Guide. All rights reserved.MFS Single-Code Coupling discussion of the Coupled-Field Analysis Guide in the Mechanical APDL application user documentation. Release 12. refer to The ANSYS Multi-field (TM) Solver . To create an ANSYS load file using CFD-Post to transfer FSI data: 1.Unidirectional (One-Way) FSI of FSI is the simulation of an internal combustion engine. examples are presented to demonstrate the FSI capabilities using CFX by itself or with other CAE packages like ANSYS Mechanical and ANSYS Multiphysics. 133) in the ANSYS CFX-Solver Manager User's Guide. The Import ANSYS CDB Surface dialog appears. In CFX.© 2009 ANSYS. The first method requires the use of the MFS variant of the ANSYS Multi-field solver and the second method does not. For more information about how these steps are automated in the Mechanical application. and make other selections as appropriate. This is possible using the CEL to specify the motion of sub-domains or domain boundaries. conjugate heat transfer and combustion problems on deforming meshes. Also select the Associated Boundary for the surface to map onto. This method involves reading an ANSYS Coded Database (CDB) file and interpolating CFX solution data onto the mesh contained in that file. 65) in the ANSYS CFD-Post User's Guide. a given field may strongly affect. refer to Export to ANSYS Multi-field Solver Dialog (p. Using CFX Only One of the most useful examples of unidirectional FSI within CFX involves prescribed mesh deformation of fluid or solid domains. These strategies are identified in the following examples. there are a variety of strategies to efficiently execute such simulations. For information about the creation and use of profile data files. For information about using the exported results and the MFS Solver. 2. and its subsidiaries and affiliates. and exporting the SFE commands). respectively. • ANSYS Import/Export Example: One-Way FSI Data Transfer You can perform one-way FSI operations manually (by exporting CDB files from the Mechanical APDL application. Load the fluids results file. the coupling between the solution fields is predominantly unidirectional. which involves the solution of fluid flow. 75 . into CFD-Post Select File > ANSYS Import/Export > Import ANSYS CDB Surface. In the discussion that follows. CFX provides tools to facilitate the import and export of solution data in a variety of formats. refer to ANSYS Import/Export Commands (p. Inc. • For information about exporting mechanical and thermal surface data and thermal volumetric data for use with the MFS solver. Contains proprietary and confidential information of ANSYS. For information about exporting mechanical and thermal surface data for general use. of Coupled-Field Analysis Guide in the Mechanical APDL application user documentation and Use Profile Data (p. but not be affected by other fields. or by reading a sequence of pre-defined meshes. In these circumstances. respectively. Using CFX and Other CAE Software Solution data can be exported from CFX in a variety of general formats during or after execution of the CFX-Solver. Execution and run-time monitoring of the coupled simulation is performed from the CFX-Solver Manager. or Temperature. Using CFX and the Mechanical Application Communicating data between and CFX and the Mechanical application is automated by the MFX branch of the ANSYS Multi-field solver. All rights reserved. This custom solution maximizes execution efficiency and robustness. The Export ANSYS Load File dialog appears. The Mechanical application solver acts as a coupling master process to which the CFX-Solver connects. Under these conditions. Inc.1. 78). 134) in the ANSYS CFX-Solver Manager User's Guide. Tangential Stress Vector. and the data file is created.) Also select the appropriate data to export: Normal Stress Vector. Select the XML document that provides all transfer information. Once that connection is established. and greatly facilitates future extensibility. and the surface data is loaded. 19) in the ANSYS CFX-Solver Manager User's Guide). Using CFX Only Conjugate heat transfer is an example of bidirectional interaction that can be solved using the CFX-Solver only. refer to Export Results Tab (p.© 2009 ANSYS. The first three SPs are used to prepare the solvers for the calculation intensive solution process. Heat Flux. FIELDVIEW. Stress Vector. and the specification of coupling data transfers and controls in the CFX-Pre user interface. In the Export ANSYS Load File dialog. and its subsidiaries and affiliates. which takes place during the final three SPs. you can select WB Simulation Input (XML) to get XML output. 297) in the ANSYS CFX-Solver Modeling Guide The Multi-Field Analysis Using Code Coupling sub-section of the Coupled-Field Analysis Guide in the Mechanical APDL application user documentation Coupled simulations begin with the execution of the Mechanical application and CFX field solvers. Click OK. Select File > ANSYS Import/Export > Export ANSYS Load File. select a filename to which to save the data. the solvers advance through a sequence of six pre-defined synchronization points (SPs). These final SPs define a sequence of coupling steps. “Sequence of Synchronization Points” (p. 5. data is communicated between the CFX and the Mechanical application field solvers through standard internet sockets using a custom client-server communication protocol. examples are provided below that demonstrate the variety of strategies to execute such simulations. MSC Patran. select the imported ANSYS mesh object.1 . each field solver gathers the data it requires from the other solver in order to advance to the next point. see the Workbench > Workbench Help > System > Custom Systems > FSI: Fluid Flow (CFX) > Static Structural section in the ANSYS documentation. 166) in the ANSYS CFX-Pre User's Guide. 76 Contains proprietary and confidential information of ANSYS. refer to Generic Export Options (p. EnSight and custom data from CFX results files. Bidirectional (Two-Way) FSI In some simulations. (Alternatively. For details. For the Location parameter value. Refer to the following sections for more information: • • Coupling CFX to an External Solver: ANSYS Multi-field Simulations (p. For information about the extraction and export of CGNS. the ability to reach a converged solution will likely require the use of bidirectional FSI. Note that a dedicated MFX-ANSYS/CFX tab is also provided in the ANSYS Product Launcher to begin execution of the coupled simulation (see General Procedure (p. Click Save. For information about the export of data in CGNS format during the execution of the solver. As for unidirectional interaction. Under File Format select ANSYS Load Commands (FSE or D). . each of which consists of one or Release 12. as illustrated in Figure 5. In this branch of the ANSYS Multi-field solver. there is a strong and potentially non-linear relationship between the fields that are coupled in the Fluid Structure Interaction. Heat Transfer Coefficient. Inc.Bidirectional (Two-Way) FSI • 4. The one-way FSI data transfer described above is performed automatically when using the FSI: Fluid Flow (CFX) > Static Structural custom system in ANSYS Workbench. Setup requires creation of the fluid and solid domain/physical models in the CFX-Pre and the Mechanical application user interfaces. At each of these SPs. Release 12. All rights reserved. Contains proprietary and confidential information of ANSYS. Inc. Stagger iterations are repeated until a maximum number of stagger iterations is reached or until the data transferred between solvers and all field equations have converged. each field solver gathers the data it requires from the other solver. 77 . During every stagger iteration. and solves its field equations for the current coupling step.Bidirectional (Two-Way) FSI more stagger/coupling iterations. The latter guarantees an implicit solution of all fields for each coupling step. Inc.1 .© 2009 ANSYS. and its subsidiaries and affiliates. All rights reserved. Inc. 78 Contains proprietary and confidential information of ANSYS.© 2009 ANSYS.1 .Bidirectional (Two-Way) FSI Figure 5.1. . Sequence of Synchronization Points Release 12. Inc. and its subsidiaries and affiliates. 1 . Release 12. and its subsidiaries and affiliates. Contains proprietary and confidential information of ANSYS.© 2009 ANSYS. All rights reserved.Bidirectional (Two-Way) FSI Using CFX and Other CAE Software Third party code-coupling software or proprietary interfaces provided by the CAE software vendors can also be used in conjunction with CFX. Inc. 79 . Inc. Please contact those software providers and your CFX service representative for more information. © 2009 ANSYS. Contains proprietary and confidential information of ANSYS. All rights reserved. Inc.Release 12.1 . and its subsidiaries and affiliates. Inc. . It is part of a series that provides advice for using ANSYS CFX in specific engineering application areas. 291)]. among other demands. Contains proprietary and confidential information of ANSYS. Nevertheless. Estimation and Validation An evaluation of CFD capabilities has to ensure that the different types of errors are identified and. forces. validation. 82) General Best Practice Guidelines (p. CFX Best Practices Guide for Numerical Accuracy This guide provides best practice guidelines for Computational Fluid Dynamics (CFD) simulation and documentation of the verification.1 . Inc. The strategies for the reduction and evaluation of numerical errors have been developed for single-phase flows.Chapter 6. Also in these cases. These difficulties will be greatly increased by the inclusion of multi-phase physics and unsteady effects. It is known from single-phase studies that the quantification and documentation of modeling errors (as in turbulence models. From a physical standpoint. 97) This guide is aimed at users who have moderate or little experience using ANSYS CFX. treated separately. An Approach to Error Identification. where extreme grid refinement will eventually capture the vortex shedding of the mixing layer). It might be not possible to rigorously perform the error estimation and reduction procedures described in the following sections for the complex demonstration cases. Release 12.© 2009 ANSYS. An essential quantity in the quality assurance procedure is the definition of target variables. that solutions are provided for grids and with timesteps that are fine enough so that numerical errors can be neglected. et cetera) can be achieved only if the other major sources of errors are reduced below an “acceptable” level. Convergence studies can be based on these variables without a reference to the grid used in the simulation. Based on these strategies. The current guidelines are adapted from Best Practice Guidelines developed for the nuclear reactor safety applications [143 (p. All rights reserved. such as the wall heat transfer along a certain line. They will mainly be scalar (integral) quantities (for instance. which require a higher degree of grid resolution than usually necessary for single-phase flows. In order to tackle the problem.and multi-phase flow formulations. as far as possible. and are mathematically similar. This would result in solutions that would be of little use for the validation goals. it is even more important to follow a stringent documentation procedure and to list the possible deficiencies and uncertainties in the simulations. It describes: • • • • An Approach to Error Identification. They are both based on (ensemble) averaged equations. and with other uncertainties in initial conditions and boundary conditions not evaluated. the worst strategy would be to avoid the subject and to provide solutions on a single grid. and demonstration test cases. this would mean. and its subsidiaries and affiliates. Estimation and Validation (p. A danger of integral or local scalar quantities is that they might not be sensitive enough to detect local changes in the solutions under grid refinement. 89) Selection and Evaluation of Experimental Data (p. Inc. There is no principal difference between the single. One of the additional complication lies in the presence of sharp interfaces between the phases. However. these quantities are of immediate meaning to engineers and allow them to understand the uncertainty from a physical standpoint. procedures have to be defined that can be used for the test case simulations. multi-phase flows have a higher affinity to physical instabilities that might be suppressed on coarse grids. In addition. 81 . the spirit behind the guidelines should be followed and carried as far as possible. An example is the blunt trailing edge of an airfoil. It is to be kept in mind that the brute application of procedures might not lead to the desired results. with a single timestep. 81) Definition of Errors in CFD Simulations (p. They can also be used for an asymptotic evaluation of convergence on unstructured meshes. In an ideal world. It is then required that you list the most promising strategies in order to reduce or avoid these errors. besides the obviously higher demands on model formulation. (This effect is sometimes also observed in single-phase flows. there are however significant additional challenges due to the presence of the different phases. and maximum temperature) or one-dimensional distributions. heat transfer rates. it is necessary to first define the different type of errors that can impact a CFD simulation. but appear under grid refinement. Even more important. the best attempt should be made to follow the principal ideas and to avoid single grid solutions without sensitivity studies. This is not a trivial task and the separation of errors cannot always be achieved. For these cases. This should be kept in mind during the analysis. A typical example is insufficient information on the boundary conditions. They are the difference between the exact solution of the model equations and the numerical solution. 82) Numerical errors result from the differences between the exact equations and the discretized equations solved by the CFD code. and its subsidiaries and affiliates. They are usually a result of programming errors. for example. Definitions on the different types of test cases as well as on the requirements for the project are given in Selection and Evaluation of Experimental Data (p. 97). For turbulent flows. 88). 82 Contains proprietary and confidential information of ANSYS. 84) Round-off Error (p. It is therefore required to select the project test cases with attention to potential error sources and experimental uncertainties. 88) User errors result from incorrect use of CFD software and are usually a result of insufficient expertise by the CFD user. 82) Spatial Discretization Errors (p. Numerical Errors Numerical Errors are of the following types: • • • • • • Solution Errors (p. combustion. two-fluid models for two-phase flows. these errors can be reduced by an increased spatial grid density and/or by smaller timesteps. • Modeling Errors (p. The relative solution error can be formally defined as: 1 2 The Navier-Stokes equations for single-phase. 83) Iteration Errors (p. 85) Solution Errors The most relevant errors from a practical standpoint are solution errors2. • Software Errors (p. and multi-phase flows by empirical models. • User Errors (p. 85) Solution Error Estimation (p. For consistent discretization schemes. All rights reserved. Inc. Newtonian fluids Sometimes also called ‘discretization errors' Release 12. Definition of Errors in CFD Simulations CFD simulations have the following potential sources for errors or uncertainties: • Numerical Errors (p. These data can introduce significant errors into the comparison. Software errors are the result of an inconsistency between the documented equations and the actual implementation in the CFD software.© 2009 ANSYS. A more detailed definition of the different errors follows. 88) Application uncertainties are related to insufficient information to define a CFD simulation. 87) Modeling errors result from the necessity to describe flow phenomena such as turbulence. the necessity for using empirical models derives from the excessive computational effort to solve the exact equations1 with a Direct Numerical Simulation (DNS) approach. • Application Uncertainties (p.Definition of Errors in CFD Simulations Validation studies have to be based on experimental data.1 . . Other examples are combustion models and models for interpenetrating continua. Inc. Errors can be reduced or avoided by additional training and experience in combination with high-quality project management and by provision and use of Best Practice Guidelines and associated checklists. Turbulence models are therefore required to bridge the gap between the real flow and the statistically averaged equations. 83) Time Discretization Errors (p. Numerical Errors Es = fexact − f numeric fexact (Eq. 6.1) Equation 6.1 (p. 83) is valid for every grid point for which the numerical solution exists. A global number can be defined by applying suitable norms, as: Es = fexact − f numeric fexact (Eq. 6.2) The goal of a numerical simulation is to reduce this error below an acceptable limit. Obviously, this is not a straightforward task, as the exact solution is not known and the error can therefore not be computed. Exceptions are simple test cases for code verification where an analytical solution is available. Given a grid spacing Δ, and the truncation error order of a consistent discretization scheme, p, a Taylor series can be written to express the exact solution as: f exact = f numeric + c Δ p + HOT In other words, the numerical solution converges towards the exact solution with the p Analogous definitions are available for time discretization errors. th (Eq. 6.3) power of the grid spacing. Spatial Discretization Errors Spatial discretization errors are the result of replacing the analytical derivatives or integrals in the exact equations by numerical approximations that have a certain truncation error. The truncation error can be obtained by inserting a Taylor series expansion of the numerical solution into the different terms of the discretized equations: f numerical = f exact + ∑ ∞ 1ci f i= (i ) th (i ) Δi (Eq. 6.4) where f is the i derivative of the exact solution at a given location. An example is a central difference for a spatial derivative: ∂f ∂x ≈ x i +1 − x i −1 (1) (1) f i +1 − f i −1 = ( f exact + f − ( f exact − f =f (1) Δ x + c 2f Δ x + c 2f (2) (2) Δ x 2 + c 3f Δ x − c 3f 2 (3) (3) Δx 3 + HOT ) / ( 2Δx ) Δx + HOT)/(2Δx ) 3 (Eq. 6.5) + o ( Δx 2 ) This formulation has a truncation error of order 2 and is therefore second-order accurate. The overall truncation error order of the spatial discretization scheme is determined by the lowest order truncation error after all terms have been discretized. In the o Δ x ( 2 ) term of Equation 6.5 (p. 83), the leading term is proportional to f (3) Δ x 2. First-order upwind (2) differencing of the convective terms yields truncation errors o ( Δ x ) with leading term proportional to f Δ x. This term then contributes to the diffusion term (numerical/false diffusion), which is most dangerous in 3D problems with grid lines not aligned to the flow direction. These schemes enhance the dissipation property of the numerical algorithm (see for example, Ferziger and Peric [141 (p. 290)]) and are not desirable in high-quality CFD simulations. From a practical standpoint, it is important to understand that for a first-order method, the error is reduced to 50% by a doubling of the grid resolution in each spatial direction. For a second-order method, it is reduced to 25% for the same grid refinement. Time Discretization Errors Time adds another dimension to a CFD simulation. The definition of time discretization errors is therefore similar to the definition of the spatial discretization errors. The spatial discretization usually results in a system of non-linear algebraic equations of the form: Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 83 Numerical Errors ∂φ ∂t =g (φ ) (Eq. 6.6) The error in the time discretization can again be obtained by a Taylor series expansion of the numerical formulation of this equation. With the example of a backward Euler integration: φ n +1 − φ n Δt = g φ n+ 1 ( ) (Eq. 6.7) the discretization error is: φ n + 1 − ( φ n + 1 − φ (1) n + 1 Δ t + c 2 φ (2) n + 1 Δ t 2 + HOT ) Δt = ∂ φ n +1 + c2 ∂t (Eq. 6.8) φ (2) n + 1 Δ t + HOT n+ 1 The error is therefore first-order for the time derivative. An additional complication for implicit methods comes from the inclusion of the unknown φ in the right hand side of Equation 6.7 (p. 84). In order to benefit from an implicit method, a linearization of g has to be included: g φ n+ 1 = g ( φ n ) + G ( ) Δφ Δt Δ t +o Δ t2 ; ( ) with G= ∂g ∂φ (Eq. 6.9) The resulting discretized equation is therefore: ⎡ 1 − G ⎤ φ n+ 1 − φ n = g ( φ n ) ⎢ Δt ⎥ ⎣ ⎦ ( ) (Eq. 6.10) This constitutes an implicit formulation with first-order accuracy. A second-order time differencing is not compatible with this linearization of the right hand side, as the linearization introduced a first-order error in Δ t. In order to be able to satisfy the implicit dependency of the right hand side on the time level n + 1 more closely, inner iterations (or coefficient loops) are frequently introduced: φ n + 1, m + 1 − φ n Δt = g φ n + 1,m + 1 ( ) −φ n + 1,m =g φ ( n+ 1 ,m ) + G (φ n+ 1 ,m + 1 ) + o (φ ) n + 1,m + 1 −φ n + 1,m 2 ) (Eq. 6.11) where an additional iteration over the index m is carried out. This equation can be reformulated as: ⎡ 1 φ n + 1, m − φ n ⎤ n + 1,m + 1 − φ n + 1,m = g φ n + 1,m − ⎢ Δ t −G ⎥ φ Δt ⎣ ⎦ ( ) ( (Eq. 6.12) This equation can be converged completely (left hand side goes to zero) in m in order to solve the original exact implicit formulation given by Equation 6.7 (p. 84). It is obvious that it is not necessary to converge the coefficient loop to zero, while the right hand side has a finite (first-order) error in Δ t. It can be shown that for a first-order time integration, one coefficient loop is consistent with the accuracy of the method. In a case where a second-order accurate scheme is used in the time derivative, two coefficient loops will ensure overall second-order accuracy of the method. Note, however, that this is correct only if the coefficient loops are not under-relaxed in any way. For explicit methods, no coefficient loops are required and the time discretization error is defined solely from a Taylor series expansion. Iteration Errors The iteration error is similar to the coefficient loop error described above. It occurs in a case where a steady-state solution is sought from an iterative method. In most CFD codes, the iteration is carried out via a (pseudo-) timestepping scheme as given in this example, which also appears above: ⎡ 1 − G ⎤ φ n+ 1 − φ n = g ( φ n ) ⎢ ⎥ ⎣ Δt ⎦ ( ) (Eq. 6.13) Zero iteration error would mean that the left hand side is converged to zero, leading to the converged solution g ( φ ) = 0. However, in practical situations, the iterative process is stopped at a certain level, in order to reduce Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 84 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Numerical Errors the numerical effort. The difference between this solution and the fully converged solution defines the iteration error. The iteration error is usually quantified in terms of a residual or a residual norm. This can be the maximum absolute value of the right hand side, g ( φ ) , for all grid points, or a root mean square of this quantity. In most CFD methods, the residual is non-dimensionalized to allow for a comparison between different applications with different scaling. However, the non-dimensionalization is different for different CFD codes, making general statements as to the required absolute level of residuals impractical. Typically, the quality of a solution is measured by the overall reduction in the residual, compared to the level at the start of the simulation. The iteration error should be controlled with the use of the target variables. The value of the target variable can be plotted as a function of the convergence level. In case of iterative convergence, the target variable should remain constant with the convergence level. It is desirable to display the target variable in the solver monitor during the simulation. Round-off Error Another numerical error is the round-off error. It results from the fact that a computer only solves the equations with a finite number of digits (around 8 for single-precision and around 16 for double-precision). Due to the limited number of digits, the computer cannot differentiate between numbers that are different by an amount below the available accuracy. For flow simulations with large-scale differences (for instance, extent of the domain vs. cell size), this can be a problem for single-precision simulations. Round-off errors are often characterized by a random behavior of the numerical solution. Solution Error Estimation The most practical method to obtain estimates for the solution error is systematic grid refinement or timestep reduction. In the following, the equations for error estimation are given for grid refinement. The same process can be used for timestep refinement. If the asymptotic range of the convergence properties of the numerical method is reached, the difference between solutions on successively refined grids can be used as an error estimator. This allows the application of Richardson extrapolation to the solutions on the different grids (Roache [139 (p. 290)]). In the asymptotic limit, the solution can be written as follows: f exact = f i + g 1 h i + g 2 h i2 + ... (Eq. 6.14) In this formulation, h is the grid spacing (or a linear measure of it) and the g i are functions independent of the grid spacing. The subscript, i, refers to the current level of grid resolution. Solutions on different grids are represented by different subscripts. The assumption for the derivation of an error estimate is that the order of the numerical discretization is known. This is usually the case. Assuming a second-order accurate method, the above expansion can be written for two different grids: f exact = f1 + g 2 h 12 + ... 2 f exact = f 2 + g 2 h 2 + ... (Eq. 6.15) Neglecting higher-order terms, the unknown function g 2 can be eliminated from this equation. An estimate for the exact solution is therefore: 2 h 2 f1 − h12 f 2 2 h 2 − h12 f exact = + HOT (Eq. 6.16) The difference between the fine grid solution and the exact solution (defining the error) is therefore: E = f exact − f1 = r 2− 1 f1 − f 2 + HOT ; with r= h2 h1 (Eq. 6.17) For an arbitrary order of accuracy, p, of the underlying numerical scheme, the error is given by: E = f exact − f1 = r p− 1 f1 − f 2 + HOT (Eq. 6.18) Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 85 Numerical Errors In order to build the difference between the solutions f1 and f 2, it is required that the coarse and the fine grid solution is available at the same location. In the case of a doubling of the grid density without a movement of the coarse grid nodes, all information is available on the coarse grid nodes. The application of the correction to the fine-grid solution requires an interpolation of the correction to the fine grid nodes (Roache [139 (p. 290)]). In the case of a general grid refinement, the solutions are not available on the same physical locations. An interpolation of the solution between the different grids is then required for a direct error estimate. It has to be ensured that the interpolation error is lower than the solution error in order to avoid a contamination of the estimate. Richardson interpolation can also be applied to integral quantities (target variables), such as lift or drag coefficients. In this case, no interpolation of the solution between grids is required. Note that the above derivation is valid only if the underlying method has the same order of accuracy everywhere in the domain and if the coarse grid is already in the asymptotic range (the error decreases with the order of the numerical method). In addition, the method magnifies round-off and iteration errors. The intention of the Richardson interpolation was originally to improve the solution on the fine grid. This requires an interpolation of the correction to the fine grid and introduces additional inaccuracies into the extrapolated solution, such as errors in the conservation properties of the solution. A more practical use of the Richardson extrapolation is the determination of the relative solution error, A1: A1 = f1 − fexact fexact (Eq. 6.19) An estimate, E1, of this quantity can be derived from Equation 6.16 (p. 85): A1 = f 2 − f1 f1 1 r p− 1 (Eq. 6.20) It can be shown (Roache [139 (p. 290)]) that the exact relative error and the approximation are related by: A1 = E1 + O h p + 1 ( ) (Eq. 6.21) Equation 6.20 (p. 86) can also be divided by the range of f1 or another suitable quantity in order to prevent the error to become infinite as f1 goes to zero. In order to arrive at a practical error estimator, the following definitions are proposed: Field error: f 2 − f1 Af = range f1 ( ) ( 1 ( r − 1) p (Eq. 6.22) Maximum error: A max = max f 2 − f1 range f1 ( ) ) 1 ( r p − 1) (Eq. 6.23) RMS error: A rms = rms f 2 − f1 range f1 ( ( ) ) 1 ( r − 1) p (Eq. 6.24) Target variable error: A rms = Θ 1− Θ 2 Θ1 1 ( r p − 1) (Eq. 6.25) where Θ is the defined target variable (list, drag, heat transfer coefficient, maximum temperature, mass flow, et cetera). Similar error measures can be defined for derived variables, which can be specified for each test case. Typical examples would be the total mass flow, the pressure drop, or the overall heat transfer. This will be the recommended strategy, as it avoids the interpolation of solutions between the coarse and the fine grid. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 86 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Modeling Errors For unstructured meshes, the above considerations are valid only in cases of a global refinement of the mesh. Otherwise, the solution error will not be reduced continuously across the domain. For unstructured refinement the refinement level, r, can be defined as follows: ⎛N ⎞ reffective = ⎜ 1 ⎟ ⎝ N2 ⎠ where N i is the number of grid points and D is the dimension of the problem. 1⁄ D (Eq. 6.26) It must be emphasized that these definitions do not impose an upper limit on the real error, but are estimates for the evaluation of the quality of the numerical results. Limitations of the above error estimates are: • • • • The solution has to be smooth The truncation error order of the method has to be known The solution has to be sufficiently converged in the iteration domain The coarse grid solution has to be in the asymptotic range. For three-dimensional simulations, the demand that the coarse grid solution be in the asymptotic range is often hard to ensure. It is therefore required to compute the error for three different grid levels, to avoid fortuitous results. If the solution is in the asymptotic range, the following indicator should be close to constant: Eh = error hp (Eq. 6.27) Modeling Errors In industrial CFD methods, numerous physical and chemical models are incorporated. Models are usually applied to avoid the resolution of a large range of scales, which would result in excessive computing requirements. The classical model used in almost all industrial CFD applications is a turbulence model. It is based on time or ensemble averaging of the equations resulting in the so-called Reynolds Averaged Navier-Stokes (RANS) equations. Due to the averaging procedure, information from the full Navier-Stokes equations is lost. It is supplied back into the code by the turbulence model. The most widely used industrial models are two-equation models, such as the k− ε or k− ω models. The statistical model approach reduces the resolution requirements in time and space by many orders of magnitude, but requires the calibration of model coefficients for certain classes of flows against experimental data. There is a wide variety of models that are introduced to reduce the resolution requirements for CFD simulations, including: • • • • Turbulence models Multi-phase models Combustion models Radiation models. In combustion models, the reduction can be both in terms of the chemical species and in terms of the turbulence-combustion interaction. In radiation, the reduction is typically in terms of the wavelength and/or the directional information. For multi-phase flows, it is usually not possible to resolve a large number of individual bubbles or droplets. In this case, the equations are averaged over the different phases to produce continuous distributions for each phase in space and time. As all of these models are based on a reduction of the ‘real' physics to a reduced ‘resolution', information has to be introduced from outside the original equations. This is usually achieved by experimental calibration, or by available DNS results. Once a model has been selected, the accuracy of the simulation cannot be increased beyond the capabilities of the model. This is the largest factor of uncertainty in CFD methods, as modeling errors can be of the order of 100% or more. These large errors occur in cases where the CFD solution is very sensitive to the model assumptions and where a model is applied outside its range of calibration. Because of the complexity of industrial simulations, it cannot be ensured that the models available in a given CFD code are suitable for a new application. While in most industrial codes a number of different models are available, there is no a priori criterion as to the selection of the most appropriate one. Successful model selection is largely based on the expertise and the knowledge of the CFD user. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 87 User Errors User Errors User errors result from the inadequate use of the resources available for a CFD simulation. The resources are given by: • • • • • • • Problem description Computing power CFD software Physical models in the software Project time frame. Lack of experience Lack of attention to detail or other mistakes. According to the ERCOFTAC Best Practice Guidelines [140 (p. 290)], some of the sources for user errors are: Often, user errors are related to management errors when insufficient resources are assigned to a project, or inexperienced users are given a too complex application. Typical user errors are: • • • • • • • Oversimplification of a given problem; for example, geometry, equation system, et cetera Poor geometry and grid generation Use of incorrect boundary conditions Selection of non-optimal physical models Incorrect or inadequate solver parameters; for example, timestep, et cetera Acceptance of non-converged solutions Post-processing errors. Application Uncertainties Application uncertainties result from insufficient knowledge to carry out the simulation. This is in most cases a lack of information on the boundary conditions or of the details of the geometry. A typical example is the lack of detailed information at the inlet. A complete set of inlet boundary conditions is composed of inflow profiles for all transported variables (momentum, energy, turbulence intensity, turbulence length scale, volume fractions, et cetera). This information can be supplied from experiments or from a CFD simulation of the upstream flow. In most industrial applications, this information is not known and bulk values are given instead. In some cases, the detailed information can be obtained from a separate CFD simulation (for instance a fully developed pipe inlet flow). In other cases, the boundaries can be moved far enough away from the area of interest to minimize the influence of the required assumptions for the complete specification of the boundary conditions. Typical application uncertainties are: • • • Lack of boundary condition information Insufficient information on the geometry Uncertainty in experimental data for solution evaluation. Software Errors Software errors are defined as any inconsistency in the software package. This includes the code, its documentation, and the technical service support. Software errors occur when the information you have on the equations to be solved by the software is different from the actual equations solved by the code. This difference can be a result of: • • • • Coding errors (bugs) Errors in the graphical user interface (GUI) Documentation errors Incorrect support information. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 88 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. such as aspect ratio. Avoid jumps in grid density.© 2009 ANSYS. negative volumes. In general. These should be incorporated through a suitable model. It is essential for mesh generation to have closed volumes. after the import of CAD-data. assessment of the mesh quality before performing a large and complex CFD analysis is very important. A careful study of the CFD code documentation and other literature on the numerical methods as well as the physical models is highly recommended. Inc. Aspect ratios may. day-to-day interaction with a CFD expert/manager is required to avoid major quality problems. symmetry planes Local details. The reader is referred to the user guides of the various mesh generators and CFD solvers for more information on these cells and mesh parameters. Growth factors should be smaller than 1. Geometry Generation Before the grid generation can start. Aspect ratios may be larger than that in unimportant regions. the geometry has to be created or imported from CAD-data. Contains proprietary and confidential information of ANSYS. the near-wall aspect ratios can be of the order of 105-106. Inc. It has to be ensured that these changes do not influence the flow to be computed. Frequently. For a given user. wall roughness or porous elements) are not included in the geometrical model. right handiness. internal angle. The number of cells in the mesh should be taken sufficiently large. For well resolved boundary layers at high Re numbers. The various CAD-data formats do not always contain these closed volumes. these errors can only be minimized by good project management and thorough interaction with others. Therefore. such that an adequate resolution is obtained for the representation of the geometry of the flow domain and the expected flow phenomena in this domain. the CAD-data has to be altered in order to create the closed volumes. it is necessary to have procedures for the estimation of the different errors described in Definition of Errors in CFD Simulations (p. In both cases. Therefore. Grid Generation In a CFD analysis.1 . A structured work plan with intermediate results is important for intermediate and long-term projects.3. be larger than that in the boundary layers. benchmark studies are recommended to enable you to understand the capabilities and limitations of CFD methods. Furthermore. 89 . and its subsidiaries and affiliates. face warpage. Recommendations for grid generation are: • Avoid high grid stretching ratios. the thoroughness. 82). A comparison of different CFD methods is desirable. cracks. All rights reserved. • • • • Aspect ratios should not be larger than 20 to 50 in regions away from the boundary. and should. The main goal is to reduce the solution error to a minimum with given computer resources. and tetrahedral quality. A good mesh quality is essential for performing a good CFD analysis. the CAD-data has to be adapted (cleaned) before it can be used for mesh generation.General Best Practice Guidelines General Best Practice Guidelines In order to reduce the numerical errors. Most of the mesh generators and CFD solvers offer the possibility of checking the mesh on several cells or mesh parameters. but not always possible. In case of inexperienced users. geometrical features with dimensions below the local mesh size (for example. All these computational cells together form the so-called mesh or grid. • Release 12. In the case that the geometry is imported from CAD-data. the flow domain is subdivided in a large number of computational cells. the data should be checked beforehand. for example. attention should be given to: • • • • The use of a correct coordinate system The use of the correct units The use of geometrical simplification. and the experience of the user. Avoiding User Errors User errors are directly related to the expertise. Model Selection and Application Modeling errors are the most difficult errors to avoid. the Navier-Stokes equations are usually time. information is lost. free jets. Avoid the presence of arbitrary grid interfaces. which is then fed back into the equations by a turbulence model. The resulting equations are the RANS equations. or changes in element types in critical regions. Numerical diffusion is high when computational cells are created that are not orthogonal to the fluid flow. In these methods. Due to the averaging procedure. It is therefore required that you gather all available information on the validation of the selected model. et cetera). The most important factor for the reduction of modeling errors is the quality of the models available in the CFD package and the experience of the user. both from the open literature and from the code developers (vendors). In case that CFD is to be applied to a new field. Turbulence Models There are different methods for the treatment of turbulent flows. between adjacent mesh parts. Inc. Judge the mesh quality by using the possibilities offered by the mesh generator. It should be demonstrated that the final result of the calculations is independent of the grid that is used. This is a very challenging requirement that often requires the use of grids that are aligned with the shear layers. it is recommended that you interact with the model developer or expert to ensure the optimal selection and use of the model. large solution gradients.© 2009 ANSYS. the selection of appropriate indicator functions for the adaptation is essential for the success of the simulations.or ensemble-averaged. . If possible. any important shear layer in the flow (boundary layer. Inc. as they cannot be reduced systematically. in order to gain confidence that the physical models are adequate for the intended simulation. mixing layer. There is also a strong interaction between modeling errors and the time and space resolution of the grid. wakes. If possible. In classical CFD methods. Avoid non-scalable grid topologies. before grid generation has started. Avoid non-orthogonal. for example. 90 Contains proprietary and confidential information of ANSYS.1 . If several modeling options are available in the code (as is usually the case for turbulence. Some CFD methods allow the application of grid adaptation procedures. for example. such as aspect ratio. unstructured tetrahedral meshes. in (thin) boundary layers. Most mesh generators offer checks on mesh parameters. modeling errors can only be estimated in cases where the validation of the model is ‘close' to the intended application. reducing the resolution requirements by many orders of magnitude. The amount of information that has to be provided by the turbulence model can be reduced if the large time and length scales of the turbulent motion are resolved. determine the size of the cells adjacent to wall boundaries where turbulence models are used. negative volumes. right handiness. it is recommended that you carry out the simulation with different models in order to test the sensitivity of the application with respect to the model selection. et cetera) should be resolved with at least 10 nodes normal to the layer. The resolution has to be sufficient for the model selected for the application. The need for a model results from the inability of CFD simulations to fully resolve all time and length scales of a turbulent motion. This is usually done by comparison of the results of calculations on grids with different grid sizes. internal angle. In principle. An arbitrary grid interface occurs when there is no one-to-one correspondence between the cell faces on both sides of a common interface. avoid computational cells that are not orthogonal to the fluid flow. cracks. As a general rule. They should be based on the most important flow features to be computed. All rights reserved. mesh refinements. Model validation is essential for the level of confidence you can have in a CFD simulation. combustion and multi-phase flow models). regions with high gradients or large changes such as shocks. Use a finer and more regular grid in critical regions. and its subsidiaries and affiliates. In these methods. The equations for this so-called Large Eddy Simulation (LES) Release 12. In case you have personal access to a modeling expert in the required area. and tetrahedral quality. it is recommended that you carry out additional validation studies. face warpage.Model Selection and Application • • • • • Avoid poor grid angles. Non-scalable topologies can occur in block-structured grids and are characterized by a deterioration of grid quality under grid refinement. the grid is refined in critical regions (high truncation errors. However. All scales smaller than the resolution of the mesh are modeled and all scales larger than the cells are computed. consideration has to be given to its numerical properties and the required computer power. All rights reserved. Typical applications are: • • • Airplane. RANS methods are the most widely used approach for CFD simulations of industrial flows. Inc. These models have typically been optimized for aerodynamic flows and are not recommended as general-purpose models. There are curvature correction models available. but shows a severe free-stream dependency. the complex models cannot be converged at all. It is often observed that more complex models are less robust and require many times more computing power than the additional number of equations would indicate. for instance by Kato and Launder [128 (p. An important weakness of standard two-equation models is that they are insensitive to streamline curvature and system rotation. the code becomes unstable and the solution is lost. or. The challenge for the user of a CFD method is to select the optimal model for the application at hand from the models available in the CFD method. et cetera. Contains proprietary and confidential information of ANSYS. this can lead to an over-prediction of turbulent mixing and to a strong decay of the core vortex.1 . Models that are more complex have been developed and offer more general platforms for the inclusion of physical effects. One-equation Models A number of one-equation turbulence models based on an equation for the eddy viscosity have been developed over the last years. The standard two-equation models can also exhibit a strong build-up of turbulence in stagnation regions. due to their modeling of the production terms. see Wilcox [30 (p. have been largely replaced by more general transport equation models. 91 . blades. Menter [9 (p. Two-equation Models The two-equation models are the main-stand of industrial CFD simulations. The most popular models are the standard model and different versions of the k− ω model. accuracy and robustness. Frequently. In most cases. Even turbulence experts cannot always agree as to which model offers the best cost-performance ratio for a new application. Particularly for swirling flows. due to their limitations in generality and their geometric restrictions. 278)]. but they have not been generally validated for complex flows. They are based on the description of the dominant length and time scale by two independent variables. as the results are strongly dependent on the user input. The lowest level of turbulence models that offer sufficient generality and flexibility are two-equation models. The standard k− ω model of Wilcox is the most well known of the k− ω based models. Alternative formulations are available. Different CFD groups have given preference to different models for historical reasons or personal experiences. and its subsidiaries and affiliates. It is most appropriate for free shear flows. The most complex RANS model used in industrial CFD applications are Second Moment Closure (SMC) models. airfoils.Model Selection and Application method are usually filtered over the grid size of the computational cells. 276)]. The use of algebraic models is not recommended for general flow simulations. this approach requires the solution of seven transport equations for the independent Reynolds stresses and one length (or related) scale. This information can be obtained from validation studies carried out with the model. Instead of two equations for the two main turbulent scales.and wing flows External automobile aerodynamics Flow around ships. there are indications as to the range of applicability of different turbulence closures. Inc. using algebraic formulations. This approach is several orders of magnitude more expensive than a RANS simulation and is therefore not used routinely in industrial flow simulations. It is therefore not recommended for general industrial flow simulations. They should be used for flows around rods. In addition to the accuracy of the model. 289)]. in the worst case. Several modifications are available to reduce this effect. as the length scales near the solid walls are usually very small and require small cells even for the LES method. it cannot be specified beforehand which model will offer the highest accuracy.© 2009 ANSYS. Release 12. the Shear Stress Transport (SST) model. see for example. Early methods. for both implementation and accuracy considerations. They offer a good compromise between complexity. It is not trivial to provide general rules and recommendations for the selection and use of turbulence models for complex applications. the grid convergence can be tested using averaged quantities resulting from the LES simulation. it is expensive to perform several LES simulations and grid refinement will therefore be more the exception than the rule. The current recommendation is to use the SAS model. experience has shown that SMC models are often much harder to handle numerically. but from an already available solution from a two-equation (or simpler) model. or other blunt bodies). In addition. LES is not yet a widely used industrial approach. One of the weak points of the SMC closure is that the same scale equations are used as in the two-equation framework. Due to the high computing requirements of LES. The most appropriate area will be free shear flows. Inc. modern developments in the turbulence models focus on a combination of RANS and LES models. as it has less grid sensitivity than the DES formulation. Two simulations on different grids are therefore not comparable by asymptotic expansion. which have to be modeled explicitly in a two-equation framework. In case that SAS does not provide an unsteady solution. 289)]. All rights reserved. the resolution requirements are much higher. This property of the LES also indicates that (non-linear) multigrid methods of convergence acceleration are not suitable in this application. as they are based on different levels of the eddy viscosity and therefore on a different resolution of the turbulent scales. flow behind a building. as they have a restricted domain in the wall normal direction.1 . There are two alternatives of such methods available in ANSYS CFX. the DES model should be applied. the models usually have to be started from the initial condition. Inc. However. The internal flows (pipe flows. From a theoretical standpoint. as the near-wall turbulent length scales become much smaller. The model can introduce a strong non-linearity into the CFD method. 281)]. The main reason is that the turbulence model adjusts itself to the resolution of the grid. if the LES model is not based on the grid spacing. Large Eddy Simulation Models LES models are based on the numerical resolution of the large turbulence scales and the modeling of the small scales. channel flows) are in between. 291)]). Again. due to the large cost of the required unsteady simulations. Some of these models show the proper sensitivity to swirl and system rotation. the problem can be avoided.© 2009 ANSYS. This reduces some of the numerical problems of the SMC approach. but on a pre-specified filter-width. It should be noted that both model formulations require small timesteps with a Courant number of CFL<1.or the ω-equation. [144 (p. This is possible only in steady state simulations. As the scale equation is typically one of the main sources of uncertainty. The first alternative is called Scale-Adaptive-Simulation (SAS) model (Menter and Egorov [130 (p. 289)]. [131 (p. where no additional modifications are required. but small scales have to be resolved in the other two directions. as it allows quantifying the influence of the turbulence model on the solution. it is found that SMC models do not consistently produce superior results compared to the simpler models. leading to numerical problems in many applications. For boundary layer flows. You are encouraged to read the original references before applying these models. [145 (p. This would allow reaching grid-independent LES solutions above the DNS limit. On a more global level.Model Selection and Application Second Moment Closure (SMC) Models SMC models are based on the solution of a transport equation for each of the independent Reynolds stresses in combination with the ε. The difference between the solutions is a measure of the influence of the turbulence model and therefore an indication of the modeling uncertainty. 291)]. For unsteady flows. 291)]). LES is a very expensive method and systematic grid and timestep studies are prohibitive even for a pre-specified filter. The goal is to cover the wall boundary layers with RANS and to allow unsteady (LES-like) solutions in largely separated and unsteady flow regions (for example. it offers an important sensitivity study. It is one of the disturbing facts that LES does not lend itself naturally to quality assurance using classical methods. 92 Contains proprietary and confidential information of ANSYS. SMC models are usually not started from a pre-specified initial condition. The averaged LES results can be analyzed in a similar way as RANS solutions (at least qualitatively). It is therefore recommended that you fully converge the two-equation model solution and save it for a comparison with the SMC model solution. The second alternative is called Detached Eddy Simulation (DES) (Spalart [146 (p. It is essentially an improved Unsteady RANS (URANS) method that develops LES-like solutions in unstable flow regimes. In addition. LES will be applicable in the near future. For certain classes of applications. implemented in the version of Strelets [58 (p. SMC models are also superior for flows in stagnation regions. where the large scales are of the order of the solution domain (or only an order of magnitude smaller). Wall Boundary Conditions There are generally three types of boundary conditions that can be applied to a RANS simulation: Release 12. . LES simulations do not easily lend themselves to the application of grid refinement studies both in the time and the space domain. These models offer generally a wider modeling platform and account for certain effects due to their exact form of the turbulent production terms. and its subsidiaries and affiliates. 93). For eddy viscosity models.1 . In the case that significantly coarser grids are used. as they allow for an accurate near-wall treatment over a wide range of grid spacings. In addition. which automatically switch from a low-Re formulation to wall functions based on the grid spacing you provide. the solution will deteriorate from a certain level on. In combination with the k− ε model. If the resolution becomes too fine. Mixed formulation (automatic near-wall treatment) In ANSYS CFX. Recommendations for Model Selection • • • • Avoid the use of classical wall functions. The treatment of the energy equation is therefore similar to the treatment of the momentum Release 12. Avoid strict low-Re number formulations. In this case. hybrid methods are available for all ω-equation based turbulence models (automatic near-wall treatment). the resolution of the boundary layer is no longer ensured. All rights reserved. Inc. The lower limit on the grid resolution for standard wall functions is a severe detriment to a systematic grid refinement process. On the downside. alternative formulations (scalable wall functions) have become available. + + Heat Transfer Models The heat transfer formulation is strongly linked to the underlying turbulence model. 93 . the heat transfer simulation is generally based on the analogy between heat and momentum transfer.© 2009 ANSYS. They can be applied to a range of grids without immediate deterioration of the solution (default in ANSYS CFX). This is very hard to ensure for all walls of a complex industrial application. These formulations provide the optimal boundary condition for a given grid. the heat transfer prediction is based on the introduction of a molecular and a turbulent Prandtl number. use scalable wall functions. instead of an improved accuracy of the solution with grid refinement. classical low-Re models require a very fine near-wall resolution of y ∼ 1 at all wall nodes. most low-Re extensions of turbulence models are quite complex and can reduce the numerical performance or even destabilize the numerical method. as no additional assumptions are required concerning the variation of the variables near the wall. use an automatic wall treatment in combination with SST turbulence model (default in ANSYS CFX). leading to a reduction in the number of cells and to a more moderate (and desirable) aspect ratio of the cells (ratio of the longest to the smallest side in a structured grid). Recently. 291)]. the first grid spacing can be too small to bridge the viscous sublayer. the logarithmic profile assumptions are no longer satisfied. For more accurate simulations. Wall functions eliminate the need to resolve the very thin viscous sublayer. the wall shear stress and the wall heat transfer can be reduced significantly below their correct values.Model Selection and Application • • • Wall Function Boundary Conditions (p. 93) Integration to the wall (low-Reynolds number formulation) (p. Integration to the wall (low-Reynolds number formulation) The use of low-Reynolds (low-Re) number formulations of turbulence models for the integration of the equations through the viscous sublayer is generally more accurate. because you have to ensure that the grid resolution near the wall satisfies the wall function requirements. which allow for a systematic grid refinement when using wall functions. Contains proprietary and confidential information of ANSYS. Standard wall functions are therefore not recommended for systematic grid refinement studies. Menter and Esch [142 (p. and its subsidiaries and affiliates. they are the most desirable. Inc. Given the eddy viscosity of the two-equation model. Wall Function Boundary Conditions Standard wall functions are based on the assumption that the first grid point off the wall (or the first integration point) is located in the universal law-of-the-wall or logarithmic region. unless it is ensured that all near-wall cells are within the resolution requirements of the formulation. as required by the best practice approach. High aspect ratios can result in numerical problems due to round-off errors. From a best practice standpoint. as they are inconsistent with grid refinement. In other words. accurate boundary layer simulations do not depend only on the y near-wall spacing. 93) Mixed formulation (automatic near-wall treatment) (p. standard wall function formulations are difficult to handle. leading eventually to a singularity of the numerical method. but also require a minimum of at least 10 grid nodes inside the boundary layer. On the other hand. You have to ensure that both limits are not overstepped in the grid generation phase. However. If the grid becomes too coarse. evaporation. Alternative assumptions have to be proposed and the sensitivity of the solution to these assumptions has to be evaluated by case studies (alteration of inflow profiles. Multi-Phase Models Multi-phase models are required in cases where more than one phase is involved in the simulation (phases can also be non-miscible fluids). boiling). with the two extremes of small-scale mixing of the phases or a total separation of the phases by a sharp interface. Interphase transfer terms have to be modeled to account for the interaction of the phases. Inc. Additional models are required for flows with mass transfer between the phases (condensation. In these flows. You should select target variables that: Release 12. for example. once the grids are available and the basic physical models have been defined. CFD Simulation This section provides recommendations concerning the optimal application of a CFD method. In the case that the assumptions have to be made concerning any input to a CFD analysis. A separate set of mass. the interaction between the particles can usually be neglected. Euler-Euler methods can be applied to separated and dispersed flows by changing the interface transfer model. In most cases.Reduction of Application Uncertainties equations. There is a wide variety of multi-phase flow scenarios. and energy conservation equations is solved for each phase. superimposed on the trajectory. Turbulence is usually accounted for by a random motion. The uncertainty can be minimized by interaction with the supplier of the test case. they have to be communicated to the partners in the project. Target Variables In order to monitor numerical errors. Document the sensitivity of the solution on the assumptions.1 . Perform a sensitivity analysis with at least two settings for each arbitrary parameter. . No additional transport equations are required for the turbulent heat transfer prediction. Recommendations are: • Identify all uncertainties in the numerical setup: • • • • • Geometry reduction Boundary condition assumptions Arbitrary modeling assumptions. The Euler-Euler formulation is based on the assumption of interpenetrating continua. and its subsidiaries and affiliates. The method integrates the three-dimensional trajectories of the particles based on the forces acting on them from the surrounding fluid and other sources. For SMC models. Inc. or droplets in a surrounding fluid. bubble diameter. different types of models are available. bubbles. thereby reducing the complexity of the problem significantly.© 2009 ANSYS. These models can be applied in the form of correlations for a large number of particles (bubbles) in a given control volume. Lagrange models solve a separate equation for individual particles. The convergence of the numerical scheme can then be checked more easily and without interpolation between different grids. et cetera). or directly at the interface between the resolved phase boundary. 94 Contains proprietary and confidential information of ANSYS. momentum. The potential uncertainties have to be documented before the start of the CFD application. et cetera. Only a few CFD methods offer this option. Lagrange models are usually applied to flows with low particle (bubble) densities. three additional transport equations must be solved for the turbulent heat transfer vector in order to be consistent with the overall closure level. different locations for arbitrary boundary conditions. Depending on the flow simulation. The boundary conditions are the same as for the momentum equations and follow the same recommendations. it is recommended that you define target variables. Reduction of Application Uncertainties Application uncertainties cannot always be avoided because the missing information can frequently not be recovered. All rights reserved. The main distinction of the models is given below. the heat transfer is computed from an eddy diffusivity with a constant turbulent Prandtl number. In addition to the residual reduction. and its subsidiaries and affiliates. Plot target variables as a function of iteration number or residual level.CFD Simulation 1. It is important for the quality of the solution and the applicability of the error estimation procedures defined in Solution Error Estimation (p. Inc. vs. The following information should be provided: • • Define target variable as given in Target Variables (p. Provide three (or more) grids using the same topology (or for unstructured meshes. such as pressure-based variables in boundary layer simulations. Report target variables as a function of r. however. For example. 2. It is desirable to have the target variable written out at every timestep in order to display it during the simulation run. This criteria should help to avoid the use of measures that are insensitive to the resolution. It is also recommended that you monitor the global balances of conserved variables. The target quantities will be given as a function of the grid density. the iteration number. Minimizing Iteration Errors A first indication of the convergence of the solution to steady state is the reduction in the residuals. 4. the simulations are carried out for a minimum of three grids. It is further recommended that the graphical comparison between the experiments and the simulations show the grid influence for some selected examples. This requires that the grid points are concentrated in areas of large solution variation. Are representative of the goals of the simulation. In addition.© 2009 ANSYS. 95 . For grid convergence tests. It is optimal if the variable can be computed during run-time and displayed as part of the convergence history.6 orders of magnitude. the recommendations may also be relevant to the iterative convergence within the timestep loop for transient simulations. residual (table).m. Depending on the numerical scheme. it is also important to provide a high-quality numerical grid. All rights reserved. 85) (Equation 6. Report global mass balance with iteration number. Contains proprietary and confidential information of ANSYS. As the order of the scheme is usually given (mostly second-order). spatial discretization errors can be influenced only by the provision of an optimal grid. such as mass. Can be computed inside the solver and displayed during run-time (optimal).and higher-order space discretization methods are able to produce high quality solutions on realistic grids.s. For the reduction of spatial discretization errors. It is well known that only second. First-order methods should therefore be avoided for high quality CFD simulations. Can be computed with existing post-processing tools. that different types of flows require different levels of residual reduction. Are sensitive to numerical treatment and resolution. 87) to test the assumption of asymptotic convergence. Minimizing Spatial Discretization Errors Spatial discretization errors result from the numerical order of accuracy of the discretization scheme and from the grid spacing. 85). This enables you to follow the development of the target variable during the iterative process. an error estimate based on the definition given in Solution Error Estimation (p. Experience shows.27 (p. a uniform refinement over all cells). Convergence is therefore monitored and ensured by the following steps: • • • • • Reduce residuals by a pre-specified level and provide residual plots. Release 12.m. A visual observation of the solution at different levels of convergence is recommended. Inc. It is also recommended that you compute the quantity given by Equation 6. momentum and energy. it is found regularly that swirling flows can exhibit significant changes even if the residuals are reduced by more than 5 .25 (p. 3. 86)) will be carried out.4 orders.1 . and maximum residual with iteration number. it is therefore required to monitor the solution during convergence and to plot the pre-defined target quantities of the simulation as a function of the residual (or the iteration number). that the coarse grid already resolves the main features of the flow.s. Plot evolution of r. 94). Other flows are well converged with a reduction of only 3 . Again.25 (p.20 steps for each period of the highest relevant frequency.Handling Software Errors • Compute solution on these grids: • • • • • Ensure convergence of the target variable in the time. 86). In case of code errors. as it usually means that no grid/timestep converged solution exists below the DNS range. Inc. they will be reported to the code developers and if possible removed. Inc. It should be noted that under strong grid and timestep refinement. using the same physical models. Check if the solution is in the asymptotic range using Equation 6. the error estimation in the time domain can be performed as a one-dimensional study. They can occur for high-Reynolds number flows where the boundary layer resolution can lead to very small cells near the wall. the sources for these differences will have to be evaluated.25 (p. All rights reserved. the relevant frequencies can be estimated beforehand and the timestep can be adjusted to provide at least 10 . 6. pre-existing software will be used. However. In case of an erratic behavior of the CFD method. the time dependency of the solution can be treated as another dimension of the problem with the definitions in Solution Error Estimation (p. In case that two CFD packages give different results for the same application. sometimes flow features are resolved that are not relevant for the simulation. 85). They are based on a systematic comparison of CFD results with verified solutions (in the optimal case analytical solutions). if Δ is replaced by the timestep. Release 12. Another example is the gradual switch to a DNS for the simulation of free surface flows with a Volume of Fluid (VOF) method (for example. 96 Contains proprietary and confidential information of ANSYS. It is assumed that all CFD packages have been sufficiently tested to ensure that no software verification studies have to be carried out in the project (except for newly developed modules). 95). Avoiding Round-Off Errors Round-off errors are usually not a significant problem. It is therefore more practical to carry out the error estimation in the time domain separately from the space discretization. the error estimators given in Solution Error Estimation (p. and its subsidiaries and affiliates. In most cases. a four-dimensional grid study would be very demanding. drop formation. An example is the (undesirable) resolution of the vortex shedding at the trailing edge of an airfoil or a turbine blade in a RANS simulation for very fine grids and timesteps. wave excitation for free surfaces. the timestep should be chosen as a fraction of: Δ t∼ Δx U (Eq. This is a difficult situation.1 . . 85) (Equation 6. Minimizing Time Discretization Errors In order to reduce time integration errors for unsteady-state simulations. The only way to avoid round-off errors with a given CFD code is the use of a double precision version. it is recommended that you use at least a second-order-accurate time-discretization scheme. Plot selected variables for the different grids in one picture. It is the task of the software developer to ensure the functionality of the software by systematic testing. the use of a double precision version is recommended. 86) for (time averaged) target variables Comparison with experimental data for different timesteps. Handling Software Errors Software errors can be detected by verification studies. Under the assumption that a sufficiently fine space discretization is available.© 2009 ANSYS. The number of digits of a single precision simulation can be insufficient for such cases.28) with the grid spacing Δ x and the front speed U . In case of unsteadiness due to a moving front. which can usually not be achieved. et cetera). 87). See Iteration Errors (p.27 (p.25 (p. Compute and report error measure for target variable(s) based on Equation 6. In principle. The following information should be provided: • • • Unsteady target variables as a function of timestep (graphical representation) Error estimate based on Equation 6.or iteration domain. 86)) can be used. Compute target variables for these solutions. Studies should be carried out with at least two and if possible three different timesteps for one given spatial resolution. 84) and Minimizing Iteration Errors (p. Usually. They must be considered an integral part of the model implementation. Verification Experiments The purpose of verification tests is to ensure the correct implementation of all numerical and physical models in a CFD method. As an example. There is no philosophical difference between the different types of test cases. The test suite for model verification must be diverse enough to check all aspects of the implementation. Testing of the new features in an expert environment might miss some of error sources like the GUI. the most frequently used correlations are those for flat plate boundary layers.© 2009 ANSYS. Inc. As analytical solutions are not always available. validation. Description For CFD code verification. All rights reserved. An example is the terminal rise velocity of a spherical bubble in a calm fluid. Quite often experimental correlations can be applied. Inc. it is not required that the simulations are in good agreement with the data. The best verification data would be the analytical solutions for simple cases that allow testing all relevant implementation aspects of a CFD code and the models implemented. The test suite should also allow testing the correct interaction of the new model with existing other features of the software. Software verification for physical models should be carried out in the same environment that the end-user has available. The more validation tests a model passes with acceptable accuracy. and its subsidiaries and affiliates. convergence can be tested against exact analytical solutions like: • • • Convection of disturbances by a given flow Laminar Couette flow Laminar channel flow. This requires information from other sources concerning the performance of the model for the test case. a fully developed channel flow does not allow to test the correct implementation of the convective terms of a transport equation. or other trustworthy publications. Requirements The only requirement for verification data is that they allow a judgement of the correct implementation of the code and/or the models. but that the differences between the simulations and the data are as expected. In most other cases. The goal of validation tests is to minimize and quantify modeling errors. Contains proprietary and confidential information of ANSYS. The same test case can be used for the different phases of model development. it is necessary to assess the accuracy of the CFD method with the help of experimental data. For instance for turbulence model verification. verification can only in limited cases be based on analytical solutions. the more generally it can be applied to industrial flows. simple experimental test cases are often used instead. without the need for comparison with one specific experiment. depending on the status of the model and the suitability of the data. and application. Verification cases should be selected before the model is implemented. Strictly speaking. Experiments are required for the following tasks and purposes: • • • Verification of model implementation Validation and calibration of statistical models Demonstration of model capabilities. For the verification of newly implemented models. Validation tests are the only method to ensure that a new model is applicable with confidence to certain types of flows. Validation cases are often called Release 12. implementation. 97 . Validation Experiments The purpose of validation tests is to check the quality of a statistical model for a given flow situation. simple experiments are used for the verification. It is recommended that you compute the test cases given by the model developer in the original publication of the model.1 .Selection and Evaluation of Experimental Data Selection and Evaluation of Experimental Data Because of the necessity to model many of the unresolved details of technical flows. et cetera)? Have any corrections been applied to the data and are they appropriate? Was there any measurement/wind or water tunnel interference? Completeness of information is also essential for the comparison of the simulation results with the experimental data. They must then be dominant in the validation case. Release 12. This includes all information required to run the simulation. All rights reserved. Frequently the information provided is not sufficient to reconstruct the data in the form required by the validation exercise. Inc. The successful simulation of these building blocks is a pre-requisite for a complex industrial flow simulation. a validation test case should be sufficiently complete to allow for an improvement of the physical models it was designed to evaluate. the influence of this information deficit has to be assessed. Requirements Validation cases are selected to be as close as possible to the intended application of the model. but a validation experiment should provide more information than isolated point measurements. the impact of the missing information has to be assessed. Completeness also relates to the non-dimensionalization of the data. Inc. transition. A validation case should have sufficient detail to identify the sources for the discrepancies between the simulations and the data. other information required by the method. multi-phase or other) will be able to cover all applications with sufficient accuracy. et cetera)? Are all the relevant physical effects known (multi-phase. The validation cases allow the CFD user to select the most appropriate model for the intended type of application. While the first three demands are clearly necessary to be able to set up and run the simulation. In an ideal case. While the mean flow quantities are often provided.© 2009 ANSYS. Typically. More desirable is the availability of field data in two-dimensional measuring planes including flow visualizations. the knowledge of all physical effects taking place in the experiment is not always considered. Typical questions are: • • • • • Is the flow steady-state or does it have a large-scale unsteadiness? Is the flow two-dimensional (axi-symmetric. as they test different aspects of a CFD code and its physical models. like: • • • • Geometry Boundary conditions Initial conditions (for unsteady flows) Physical effects involved.Validation Experiments building block experiments. Most crucial is the completeness of the data required to set up the simulation. validation data are obtained from DNS studies. The importance of this deficit can be estimated by experience with similar flows and by sensitivity studies during the validation exercise. Profiles and distributions of variables at least in one space dimension should be available (possibly at different locations). As an example. Description Examples of validation cases are flows with a high degree of information required to test the different aspects of the model formulation. Typical examples are incomplete inlet boundary conditions. Increasingly. . validation cases are geometrically simple and often based on two-dimensional or axi-symmetric geometries. Completeness of information is one of the most important requirements for a validation test case. the validation of a turbulence model for a flat plate boundary layer does not ensure the applicability of the model to flows with separation (as is known from the k− ε model). as profiles for turbulent length scales and volume fractions is frequently missing.1 . In case of missing information. This is a vague statement and cannot always be ensured. The main limitation here is in the low-Reynolds number and the limited physical complexity of DNS data. it is crucial to have a clear understanding of the overall flow in order to be able to judge the quality of a test case. It is well accepted by the CFD community and by model developers that no model (turbulence. However. The requirements for validation cases are that there should be sufficient detail to be able to compute the flow unambiguously and to evaluate the performance of the CFD method for a given target application. This is the reason why there are always multiple models for each application. but it will be more and more necessary to validate CFD methods for combined effects. Test case selection requires that the main features of the CFD models that are to be tested be clearly identified. and its subsidiaries and affiliates. 98 Contains proprietary and confidential information of ANSYS. In case that the data provided are not sufficient. Validation cases are often ‘single physics' cases. Release 12. demonstration cases often do not provide a high degree of detail. While validation studies have shown for a number of building block experiments that the physical models can cover the basic aspects of the target application. data that cannot be shown publicly are much less valuable than freely available experimental results. and its subsidiaries and affiliates. It is therefore even more essential to identify the missing information and to carry out sensitivity studies with respect to these data. It has to be ensured. Due to the limited amount of data available. This includes questions of ownership. Typically. Description For an aerodynamic study. even if error estimates are available. the demonstration cases test the ability of a method to predict combined effects. The requirements in terms of availability/openness are usually lower than for validation cases. as efficiencies. it is therefore desirable to have an overlap of experimental data that allow testing the consistency of the measurements.1 . Contains proprietary and confidential information of ANSYS. Consistency can also be judged from total balances. They are usually not appropriate to identify specific weaknesses in the physical models or the CFD codes. In terms of post-processing. a typical hierarchy would be: • • • Verification .Complete aircraft. like mass. the level of completeness of the data for demonstration cases is much lower than for validation cases. Even though the density of data is usually lower. Moreover. Unfortunately. In addition to error bounds.Airfoil or wing Demonstration . most experiments still do not provide this information. Similar hierarchies can be established for other industrial areas. Typically. For most CFD code developers. the information is usually not sufficient to carry out consistency checks. Error estimates are desirable and so are independent measurements. including geometrical complexity.Demonstration Experiments Next to the completeness of the data. the quality should satisfy the same criteria as for validation cases. are provided. the detail of the experimental data is much lower than for verification or validation cases. Examples are the same data from different experimental techniques. their quality is of primary importance for a successful validation exercise. Completeness of information to set up the test case is of similar importance as for validation cases and involves the same aspects as listed below: • • • • Geometry Boundary conditions Initial conditions (for unsteady flows) Physical effects involved. 99 . only the point data or global parameters. even if they used different models. that the data can be shown to the target audience of the simulation. The availability of the data has to be considered before any CFD validation is carried out. A demonstration case might be carried out for a single customer or one specific industrial sector. Requirements Typically. as in all cases. It is also a quality criterion when different experimental groups in different facilities have carried out the same experiment. The quality of the data is mainly evaluated by error bounds provided by the experimentalists.Flat plate Validation . Demonstration Experiments The purpose of a demonstration exercise is to build confidence in the ability of a CFD method to simulate complex flows. Quality and consistency can frequently be checked if validation exercises have already been carried out by other CFD groups. as the demonstration applies usually to a smaller audience. Inc. they cannot exclude systematic errors by the experimentalist. All rights reserved. Inc. momentum and energy conservation.© 2009 ANSYS. Release 12. Contains proprietary and confidential information of ANSYS. Inc.1 .© 2009 ANSYS. Inc. . All rights reserved. and its subsidiaries and affiliates. It is aimed at users with moderate or little experience using CFX for applications involving cavitation. When a liquid boils. inducers. Cavitation is a concern in several application areas.Chapter 7. Other problems include noise. 101 . including pumps.1. Liquid Pumps Water pumps must take in water and deliver it at a higher total pressure with an acceptable flow rate. and can be plotted in a pump performance diagram. cavitation may occur on the low pressure side of the pump. 101). All rights reserved. and its subsidiaries and affiliates.1 . causing a loss of pressure rise and/or flow rate. CFX Best Practices Guide for Cavitation This guide is part of a series that provides advice for using CFX in specific engineering application areas. Figure 7. One of the major problems caused by cavitation is a loss of pressure rise across a pump. cavitation will not occur. Cavitation should not be confused with boiling. Inc. thermal energy drives the local temperature to exceed the saturation temperature. and fuel injectors.© 2009 ANSYS. The bubbles of vapor usually last a short time. Flow Rate vs Pressure Rise for a Liquid Pump Release 12. marine propellers. water turbines. Both pump performance without cavitation and the affects of cavitation on performance will be discussed. for a given pump RPM. vibration. The next section discusses the effects of cavitation on the performance of liquid pumps. Inc. and damage to metal components. Pump Performance without Cavitation As long as the static pressure remains sufficiently high everywhere in the system. This guide describes Liquid Pumps (p. Under certain conditions. In this case. Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. as shown below. the pressure rise and flow rate are directly coupled. Contains proprietary and confidential information of ANSYS. collapsing when they encounter higher pressure. Run the solver to obtain a solution. which almost always causes a large loss of pressure rise. Procedure for Plotting Performance Curve 1. cavitation occurs.© 2009 ANSYS.1 . the solution will eventually fail to converge. .inlet is the inlet total pressure. When the inlet total pressure reaches a sufficiently low value. If you have trouble getting a converged solution. Cavitation Performance at Constant RPM and Flow Rate NPSH is the Net Positive Suction Head. a further increase in cavitation causes a sudden loss of pressure rise. 7. All rights reserved. pressure rise can actually increase slightly with small amounts of cavitation. cavitation will occur causing the pressure rise to diminish. the total pressure at the outlet drops by the same amount as at the inlet. Using CFX software. Set up a simulation with cavitation turned on and pressure levels set high enough to avoid levels of cavitation that significantly affect pressure rise. To generate this diagram. In rare cases. Since the pressure rise remains constant.Pump Performance with Cavitation Pump Performance with Cavitation If the inlet total pressure is below the critical value for a particular flow rate and RPM. and the pressure rise is measured at progressively lower inlet total pressures.2. and its subsidiaries and affiliates.1) where pT. so does the NPSH value. 102 Contains proprietary and confidential information of ANSYS. the pressure rise across the pump is constant. equal to the amount predicted by the first performance diagram. This results in a horizontal trend in the performance curve as the inlet total pressure is dropped. then use the result as an initial guess for a simulation with cavitation turned on. For the part of the test where the inlet total pressure is sufficiently high to prevent cavitation. Figure 7. The point of cavitation is often marked by the NPSH at which the pressure rise has fallen by a few percent. inlet − pv ⎞ NPSH = ⎜ ⎟ ρg ⎝ ⎠ (Eq. Before this point. In the lab. As the inlet total pressure drops. Inc. however. Inc. a quantity directly related to the inlet total pressure by the relation: ⎛ pT . a mass flow outlet boundary condition can be specified to fix the flow rate while the inlet total pressure is varied. data should be collected with a sufficient resolution (sufficiently small changes in inlet pressure) to resolve the part of the performance curve where the pressure starts to drop. and the amount of cavitation increases. Even in such cases. 2. ρ is density. the pressure rise will eventually become insufficient to maintain the required flow rate. and g is the acceleration due to gravity. Release 12. A further reduction in inlet total pressure causes more cavitation. The following performance diagram shows the effect of cavitation on pressure rise. RPM and flow rate are fixed. pv is the vapor pressure. try running a simulation with cavitation turned off. Using CFX software. remember that the vapor pressure is on an absolute scale. approaching cavitation). 103 . use the function calculator. In the latter case. In most cases. Inc. To calculate the inlet and outlet pressures. Setup To facilitate setting up typical domain settings for the cavitation of water. then plot a point in the performance diagram. Select the Rayleigh Plesset cavitation model or a User Defined Cavitation Model. set the volume fraction of vapor to zero and the volume fraction of liquid to unity. Release 12. For turbulence induced cavitation. then run the template . Contains proprietary and confidential information of ANSYS.© 2009 ANSYS. using the previous solution as the initial guess. Under Fluid Pairs for the domain. The default value of 2e-06 m is a reasonable value in most cases. Set up the problem with one of the following boundary condition combinations: 1. then turn on cavitation and use the first set of results as an initial guess.1 .e.g.ccl This file should be examined in a text editor before using it so that you understand which settings it specifies. Convergence Tips If performing a single solution. use high resolution. k-epsilon or SST). you may load a single-domain mesh. You do not need to select Free Surface Model for the purpose of simulating cavitation. When initializing the domain. Under Fluid Models for the domain..Setup 3. Cavitation models cannot be combined with other types of interphase mass transfer.ccl file: CFX/etc/model-templates/cavitating_water. Turbulence models should be chosen as usual (e. the saturation properties will already be defined in the mixture definition. These settings (represented by the Automatic setting for Volume Fraction) are used by default in CFX. such as thermal phase changes. for Mass Transfer. If performing a series of simulations using one solution to initialize the next. but you may still choose to override the Saturation Pressure by specifying it on the Fluid Pairs tab. All rights reserved. set Option to Cavitation. Lower the pressure boundary condition by about 5% to 10%. and its subsidiaries and affiliates. consider using the DES model. initially turn off cavitation. solve the cases in order of decreasing pressure (i. specify both a liquid and a vapor for the same material. select the fluid pair from the list and. 4. For advection scheme. it is strongly recommended that you select Homogeneous Model under Multiphase Options. or a specified blend factor of unity. Inc. If editing a material. Post-Processing A contour plot of volume fraction for the vapor can show where cavitation bubbles exist. For the domain fluids list. Calculate the pressure rise across the pump and the NPSH value. 5. it is sufficient to use a constant-density vapor. Repeat starting from step 2. it does not depend on the specified reference pressure. until cavitation has caused a significant loss of pump head. the Mean Diameter for cavitation bubbles represents the mean nucleation site diameter and must be specified. 2. For the Rayleigh Plesset model.. The Saturation Pressure must be defined unless the materials you have selected are the components of a homogeneous binary mixture. Inlet total pressure and outlet mass flow (recommended) Inlet velocity profile and outlet static pressure The inlet boundary condition should specify that the volume fraction of vapor is zero. 1 .Release 12. All rights reserved. Contains proprietary and confidential information of ANSYS. .© 2009 ANSYS. Inc. Inc. and its subsidiaries and affiliates. the Eddy Dissipation combustion model is a sensible choice. It is aimed at users with moderate or little experience using CFX for applications involving combustion. Inc.Chapter 8. FRC/EDM combined. Another key design goal is to minimize the emission of pollutants. Premixed Combustion Non-Premixed Combustion Commonly used for recent stationary gas turbines in power Typically used for flight engines because it is easier to generation. FRC/EDM combined. particularly oxides of nitrogen. 105) Combustion Modeling in HVAC cases (p. The Release 12. . Transient Most simulations are steady-state. The Laminar Flamelet model is applicable for turbulent flow with non-premixed combustion. and passes it to the turbine. for some cases. meaning that only two additional transport equations are solved to calculate multiple species. For the preliminary analysis of high speed turbulent flow. extinction by temperature or by mixing/chemical time scales). Flamelet (and. particularly for stationary gas turbines that operate at a constant load. Turbulence Model The k − ε turbulence model is used in many applications.1 . CFX Best Practices Guide for Combustion This guide is part of a series that provides advice for using CFX in specific engineering application areas. but cannot simulate burning velocities or flame position. Setup Steady State vs.© 2009 ANSYS. a reference pressure between 4 and 20 atmospheres is common. The combustor receives the working fluid in a compressed state. One of the key design goals for the combustor is to achieve a stable combustion process. Combustion Model The choice of combustion model depends of whether the fuel/oxidant combination is premixed. Reference Pressure Because of the high inlet pressure. and provides a robust solution at a low computational expense for multi-step reactions. burns fuel to increase its temperature. and its subsidiaries and affiliates. The following table outlines some of the differences. control variable operating conditions. Combustion Models: EDM with product limiter and/or extinction submodels. and the Reynolds Stress Model is the best choice for highly swirling flows. All rights reserved. Contains proprietary and confidential information of ANSYS. 107) Gas Turbine Combustors Gas turbines are widely used in stationary and aircraft applications. The Flamelet model uses a chemistry library. and depends upon the type of simulation you are running. Partially Premixed (Turbulent Flame Speed Closure (TFC)) Note that the EDM model usually needs adjusting for premixed combustion (for example. This guide describes: • • Gas Turbine Combustors (p. 105 Combustion Models: EDM. also the Premixed model). but the SST model should be considered for flows with separated boundary layers. As a result. Inc. the Flamelet model is a very good choice for modeling the formation of various pollutants during the combustion process. and will not predict emissions correctly. which helps to predict reduction in temperature (unlike EDM).Reactions Flamelet model predicts incomplete combustion to some extent (CO in exhaust gas). Inc. Reactions During the initial analysis of a combustor. All rights reserved. pollutants (NO) Turbulent Mixing Time Scale (Eddy Dissipation / Turbulent Kinetic Energy) Reaction Rates The variable "<my reaction>. For simulations which include Finite Rate Chemistry. It is ok to restart an EDM case from a Flamelet model solution. As a result.2 if you are having trouble converging a solution.Molar Reaction Rate" is available for every "Single Step" reaction (EDM. Convergence Tips The Equation Class Settings tab in CFX-Pre can be used to set different advection schemes and time scales for each class of equation you are solving. add a TEMPERATURE DAMPING CCL structure within a SOLVER CONTROL block. the highest values of temperature and outgoing heat flux are likely to be of primary concern. Inc. For the Eddy Dissipation Model. products. intermediate species (CO). . For multi-step Eddy Dissipation reactions.1 . For this purpose. To aid convergence. and its subsidiaries and affiliates. Release 12. multistep convergence can be aided by first running a simplified single-step simulation and using the results from the run as an initial values file for a multi-step run. the temperature damping may be applied to a particular domain or phase. O2. as follows: FLOW: SOLVER CONTROL: TEMPERATURE DAMPING: Option = Temperature Damping Temperature Damping Limit = <Real number> Under Relaxation Factor = <Real number> END END END Depending on the location of the SOLVER CONTROL block. Set the Temperature Damping Limit to 0 so that positive damping is always applied. convergence can become very difficult when a multi-step reaction contains more than about 5 steps. Such a reaction is likely to overpredict the temperature. temperature values may change sufficiently to make the solution unstable. Other reaction steps might then be added to the simulation to account for the formation of combustion byproducts. to provide a mesh of sufficient quality to resolve most of the flow features. The Under Relaxation Factor can be set to multiply changes in temperature by a value between 0 and 1. The High Resolution advection scheme is always recommended for combustion simulations because it is bounded and prevents over/undershoots. but can provide a conservative indicator of the expected temperature levels. It is ok to restart a Flamelet model from a cold solution. When a solution is converging. Care must be taken. convergence can be improved by temporarily increasing the mass fraction time scale by a factor of about 5-10. 106 Contains proprietary and confidential information of ANSYS. however. small temperature variations can result in large changes in reaction rate. You should try a factor of 0. Each reaction step has its own separate time scale. A very poor mesh will result in the scheme using a blend factor close to zero (therefore not providing a solution as accurate as expected). You should avoid restarting with the Flamelet model from an EDM solution. Post-Processing Some of the most common plots to create in CFD-Post include: • • • Mass Fractions: fuel. FRC or combined model).© 2009 ANSYS. a single-step Eddy Dissipation reaction can be used. but convergence may be very slow. The simulation will dictate the type of materials to use as a fuel. plastics and wood are also used. it is very important to correctly specify the buoyancy reference density when opening boundary conditions are used. The presence of an instantaneous fuel supply is sometimes not physical. Inc. or when the ventilation cannot be easily predicted. and can slow convergence. The choice of timestep is generally model dependent. diesel and petroleum. Setup Most simulations are set up as transient. Note When modeling buoyancy.© 2009 ANSYS. The flamelet model is more rigorous. Convergence tips Convergence can be slowed if care is not taken in the setup of buoyancy and openings. combined with an Additional Variable for toxins. but may not converge well for natural convection. In many transient cases. with either no buoyancy terms in equations or buoyancy terms in both the equations (with C3=1). All rights reserved. The Eddy Dissipation Model is widely used. where it is important to accurately model the combustion process. Contains proprietary and confidential information of ANSYS. Cellulosic materials. the amount of fuel available can be controlled by using time-dependent expressions. The RNG k − ε turbulence model is a good choice for combusting flows. The drawback is the additional computational expense involved in solving a full combustion model as part of the main solution. but will usually fall into the range 0. and is a better choice when the fire is under ventilated. and its subsidiaries and affiliates. Using a combusting fire simulation is the most accurate way to model fires in all HVAC cases. The Total Energy heat transfer model should be selected to fully model buoyancy. The SST model is also reasonable. as opposed to "inert fire" simulations. but will usually include one of more of the following: • • • • • Temperature Products (including carbon monoxide and other toxins) Visibility Wall Temperature Wall convective and radiative heat fluxes Release 12. Post-processing The most common parameters of interest in a combusting fire model are simulation-dependent. The most common fuels used are hydrocarbons such as methane. Such processes are known as "combusting fire" simulations.1 .5 s to 2 s. Inc. The SSG model is accurate. It is particularly important in cases when the fire is under-ventilated. 107 .Combustion Modeling in HVAC cases • Plots of the turbulent Damköhler number (the ratio of the turbulent time scale to the chemical time scale) Combustion Modeling in HVAC cases This section deals with the setup of combustion cases for HVAC simulations. Inc. .© 2009 ANSYS. Inc.1 .Release 12. and its subsidiaries and affiliates. All rights reserved. Contains proprietary and confidential information of ANSYS. and its subsidiaries and affiliates. Buoyancy Most HVAC cases involve flow that is affected by buoyancy. Thermal Radiation To set the radiation model for a fluid domain. 109) Convergence Tips (p. CFX Best Practices Guide for HVAC This guide discusses best practices for setting up. a Buoyancy Reference Temperature must be set as the expected average temperature of the domain.Chapter 9. Often. In this case. and Air Conditioning. In this case. Two buoyancy models are available: Full and Boussinesq. heaters. 109 . All rights reserved. it is also used as a reference to refrigeration.1 . Ventilation (or Ventilating). visit the Fluid Models panel for that domain and set the following: 1 HVAC is a reference to Heating. An incompressible fluid should be chosen only if density variations are small (a few percent or less). Contains proprietary and confidential information of ANSYS. • When fluid properties are functions of pressure. and components involved in HVAC simulations. The calculation of absolute pressure requires a Buoyancy Reference Location to be defined. • The Full buoyancy model is used if fluid density is a function of temperature and/or pressure (which includes all ideal gases and real fluids). Inc. These models are automatically selected according to the properties of the selected fluid(s). solving. preferably by specifying coordinates. and post processing an HVAC simulation: • • HVAC Simulations (p. air conditioners. Physical processes that are commonly modeled in HVAC simulations include: • • • • • • Buoyancy Thermal radiation Conjugate heat transfer (CHT) between fluids and solids. and radiators Fans/pumps Thermostats. Typical HVAC systems include the following components: Setting Up HVAC Simulations This section discusses how to set up various physical processes. Heating/cooling units such as furnaces.© 2009 ANSYS. CFD features. HVAC Simulations HVAC studies range in scale from single components (such as a radiator) to large and complicated systems (such as a climate control system for a large building). the absolute pressure is used to evaluate them. The Boussinesq model is used if fluid density is not a function of temperature or pressure. a Buoyancy Reference Density must be set as the expected average density of the domain. It is aimed at users with moderate or little experience using CFX for HVAC1 applications. Inc. Buoyancy can be activated on the Basic Settings tab of the Domain details view. it is recommended that you choose a compressible fluid because density variations will be significant. When modeling fire. 111) This guide is part of a series that provides advice for using CFX in specific engineering application areas. Release 12. the exterior boundary must be modeled as an opaque wall. and the Refractive Index. Inc. For subdomains. Material properties related to radiation. and openings. Thermal radiation properties are specified on the Boundary Details panel for each boundary of a domain that transmits radiation. Radiation escaping through a window can be modeled by specifying a non-zero emissivity (to cause radiation absorption) and either: • • Specifying a heat transfer coefficient via a CEL expression that accounts for the thermal energy lost Specifying a fixed wall temperature. Release 12. The only radiation model available for solid domains is Monte Carlo. To set up radiation for a solid domain. thermal radiation properties for boundaries. Scattering Model A scattering model should not be used if you are modeling clear air. If directed radiation is to be modeled. a spectral radiation model is recommended. Frequency (or freq). and its subsidiaries and affiliates. If a simulation contains no solid domains that transmit radiation. The boundaries of radiation-transmitting domains that interface with such a solid domain should be specified as opaque. radiation sources per unit volume are specified. Multiple isotropic sources and up to one directed source may be specified for any given wall boundary or subdomain. Wavenumber in Vacuum (or waveno). the properties that must be specified are: Emissivity and Diffuse Fraction. Spectral bands are used to discretize the spectrum and should therefore be able to adequately resolve all radiation quantities that depend on wavelength (or frequency or wave number). you may specify either the Local Temperature or an External Blackbody Temperature. The Monte Carlo and Discrete Transfer models allow radiation sources to be specified on the Sources panel for any subdomain or wall boundary. Radiation sources may be directed or isotropic. For HVAC.Setting Up HVAC Simulations Thermal Radiation Model For HVAC studies. 110 Contains proprietary and confidential information of ANSYS. Spectral Model Select either Gray or Multiband. then all fluid domains using a radiation model must use the Monte Carlo model. The material used in a domain that transmits radiation has radiation properties that specify Absorption Coefficient. if it uses radiation at all). and source strengths can be specified as expressions that depend on one or more of the built-in variables: Wavelength in Vacuum (or wavelo). Note If any solid domain uses the Monte Carlo radiation model (that is. two bands will usually suffice. When using solid domains that transmit radiation. A domain representing an opaque solid should not have a radiation model set. for boundaries. visit the Solid Models panel for that domain (each solid domain must be set up separately). All rights reserved. For opaque surfaces.© 2009 ANSYS. radiation fluxes are specified. External windows of a room can be modeled as solid domains which interface with the room (air) domain. a gray radiation model can be used for rough calculations but a spectral model should be used for more detailed modeling. A diffuse and a directed radiation source emitted from the opaque surface can be used to simulate sunlight. Inc. select either Monte Carlo or Discrete Transfer. These properties may be edited in the Materials details view. Note Radiation modeling cannot be used with Eulerian multiphase simulations. the direction vector for directed radiation can be specified by CEL expressions that depend on time (t). Monte Carlo must be used.1 . they may also be modeled as an external boundary of the room domain. The isotropic scattering model should be used if you are modeling air that contains dust or fog. In order to simulate the motion of the sun. Scattering Coefficient. outlets. . For inlets. In either case. and resistances. wall roughness) may be specified on the boundaries of a fluid domain that interface with a solid domain. specified temperature.© 2009 ANSYS. Refer to Air Conditioning Simulation (p. Boundaries between domains that model heat transfer have temperatures and thermal fluxes calculated automatically. consider volumetric sources of heat. Convergence Tips Buoyancy and coupling between the relevant equations often make convergence difficult. Release 12. 111 . Smaller timesteps may help convergence. Collections of Objects If your HVAC simulation models a large number of people/equipment/items. In CFX. Inc. Inc. Fans Fans should be represented by momentum sources if they are embedded in the domain. If you do not want to model heat transfer in a particular region. and are therefore CHT domains. Boundary conditions other than thermal boundary conditions (for example. consequently. The mesh resolution in a boundary layer affects the prediction of convective heat transfer and the temperature gradient near the wall. For walls without a specified temperature. specified heat flux. Mesh Quality Ensure that wall boundary layers have adequate mesh resolution. all solid domains must model heat transfer. Fans can also be represented by an inlet or outlet boundary condition or both. and should not have thermal boundary conditions specified. External boundaries (which can represent solids that are not explicitly modeled) require the specification of a thermal boundary condition.Convergence Tips CHT (Conjugate Heat Transfer) Domains CHT domains are solid domains that model heat transfer. the temperature gradient near the wall affects the calculated wall temperature and. Sources of thermal energy and/or radiation can be added to a subdomain of a CHT domain. This is important regardless of the type of wall heat transfer: adiabatic. or heat transfer coefficient. 275) in the ANSYS CFX Tutorials for details. and its subsidiaries and affiliates. Contains proprietary and confidential information of ANSYS.1 . do not assign the mesh for that region to any domain. All rights reserved. CO2. the amount of radiation emitted (provided that the emissivity of the wall is non-zero). Thermostats A Thermostat can be defined using a User Fortran routine. .1 . All rights reserved. Inc. Inc. Contains proprietary and confidential information of ANSYS.Release 12.© 2009 ANSYS. and its subsidiaries and affiliates. you can determine whether values for selected global quantities (such as gas hold-up) are meaningful. rather.© 2009 ANSYS. bioreactors to dissolve oxygen in broths) and to limit the exposure of micro-organisms to excessive shear imparted by mechanically driven mixers. This guide describes: • • • Bubble Columns (p. CFX includes a variety of multiphase models to allow the simulation of multiple fluid streams. Unlike multicomponent flow1. and the dispersed phase zero equation is used for the dispersed phase. Contains proprietary and confidential information of ANSYS. Setup The choice of a steady state or transient simulation depends on the type of simulation you wish to analyze. As a result.Chapter 10. Release 12. they are mixed on a macroscopic scale. 0. you can still obtain an indicator of convergence for a global quantity by creating a monitor point at some point in the domain. with a discernible interface between the fluids. the fluids are not mixed on a microscopic scale. physical instabilities (such as recirculation zones) can result in slow or stalled convergence. a multiphase flow is a flow composed of more than one fluid. and other columns that do not use a baffle. and free surface flows. For smaller columns. A transient simulation can be used to observe transient effects. but as a wall to the continuous phase. This would require solving for the gas volume fraction for a number 1 Note that a fluid in a multiphase flow may be a multicomponent mixture. Convergence Tips Sometimes. In the context of CFX. such as recirculation zones. A reasonable estimate of the time scale is given by a factor of the length of the domain divided by the velocity scale (for example. The degassing boundary behaves as an outlet boundary to the dispersed phase. Mixing efficiency can be measured in a number of ways. Each fluid may possess its own flow field. which is strongly influenced by the dispersed phase. Inc.1 . For example. It is aimed at users with moderate or little experience using CFX for applications involving multiphase flows. non-drag forces may be significant. One example is to measure the gas hold-up in the riser as a function of the superficial gas velocity. 114) Free Surface Applications (p. All rights reserved. Post-Processing The main design objective for bubble columns is efficient mixing. The Grace drag model is recommended. CFX Best Practices Guide for Multiphase This guide is part of a series that provides advice for using CFX in specific engineering application areas. 113) Mixing Vessels (p. Most bubble columns use two fluids: one continuous fluid and one dispersed fluid. droplets. In these cases. especially for modeling air/water. an analysis using a steady-state simulation is often satisfactory for monitoring global quantities. 113 . Non-drag forces become less significant with increasing size of the bubble column. The k − ε model is typically used in the continuous fluid. and its subsidiaries and affiliates. A degassing boundary condition is generally employed at the top of the bubble column. There are two types of bubble columns in general use: airlift reactors that use a baffle to separate the riser and downcomer regions. Inc.5 * L/U). or all fluids may share a common flow field. bubbles. 114) Bubble Columns Bubble columns are tall gas-liquid contacting vessels and are often used in processes where gas absorption is important (for example. The homogeneous model can be used when the interface between the two phases remains well defined and none of the dispersed phase becomes entrained in the continuous phase. The initial condition for pressure should be set to hydrostatic conditions for the specified volume fraction initialization and the buoyancy reference density. .© 2009 ANSYS. Where a Frozen Rotor interface is used. The same choice of turbulence model as for single phase simulations is appropriate. The length scale should be a geometric length scale. When using the inhomogeneous model. Mixing must be efficient. A breaking wave is one example of an inhomogeneous flow case.Mixing Vessels of simulations. The Buoyancy Reference Density should be set to the density of the least dense fluid. Setup The choice of using a steady-state or transient simulation is problem-dependent.1 . The impeller domain is a small. The recommended types are: • • Frozen Rotor: faster but cruder Transient: slower (transient analysis) but much more accurate The choice of a steady state or transient simulation is dependent on the type of interface that exists between the two domains. for example. The timestep for free surface flows should be based on a L/U (Length/Velocity) scale. you should use the homogeneous turbulence option in CFX-Pre. 114 Contains proprietary and confidential information of ANSYS. Inc. or in a breaking wave. The initial guess for velocity can be set to zero in the relative frame for each domain. Performing a transient simulation allows you to use the transient rotor/stator frame change model to account for transient effects. Release 12. The rest of the tank is represented by a stationary domain. Inc. There are two models available for free surface flow: homogeneous and inhomogeneous. Mixing Vessels Mixing vessels are widely used in the chemical industry to optimize mixing and/or heat transfer between fluids. Another option would be to use the same input parameters. power draw. the initial conditions can use step functions to set the volume fractions of the phases as a function of height. it is sometimes helpful to reduce the timestep for the volume fraction equations by an order of magnitude below that of the other equations. more reliable scale-up. each with a different mass flow rate of the dispersed phase at the sparger. The application of Computational Fluid Dynamics to address these needs results in faster and lower cost design through reduced experimentation. a steady state simulation is usually carried out. Different types of domain interfaces are available for the connection between the stationary and the rotating domains. Free Surface Applications Free Surface flow refers to a multiphase situation where the fluids (commonly water and air) are separated by a distinct resolvable interface. local shear and strain rates. An example of homogeneous free surface flow is flow in an open channel. and its subsidiaries and affiliates. around the hull of a ship. Setup Mixing vessels generally use two domains. which is given by: U buoyant = g L In addition. gas hold-up. An outlet boundary having supercritical flow should use the Supercritical option for Mass And Momentum. rotating domain which encloses the impeller. For most free surface applications. When setting boundary conditions. This requires that you set the relative pressure of the gas above the free surface at the outlet. Quantities of interest may include mixing times. Such flows occur. precise and repeatable to ensure optimum product quality. leading to higher yields and reduced waste. All rights reserved. the volume fractions can be set up using step functions to set the liquid height at each boundary. this time measuring the liquid velocity in the downcomer. The velocity scale should be the maximum of a representative flow velocity and a buoyant velocity. and better understanding of the processes. and solids distribution. and inflate the mesh in both directions from the edge of the subdomain. A technique to increase the mesh density in the region of a liquid-gas interface is to create a subdomain which occupies the same region as the liquid (or gas) phase.” (p. Release 12. The inflation layers can increase the resolution in the region of the interface and enhance the results.1 .Convergence Tips Convergence Tips The interface between the liquid and gas phase can sometimes become blurry. This could be due to physical properties (such as a breaking wave or sloshing in a vessel). the inhomogeneous model is a better choice. All rights reserved. Where the dispersed phase becomes entrained in the continuous phase.1.© 2009 ANSYS. as shown in Figure 10. “An exaggerated view of three inflation layers on each side of the uppermost subdomain boundary surface. An exaggerated view of three inflation layers on each side of the uppermost subdomain boundary surface. Inc. 115 . Inc. and its subsidiaries and affiliates. Figure 10. 115).1. Contains proprietary and confidential information of ANSYS. Release 12. .1 . Contains proprietary and confidential information of ANSYS. All rights reserved.© 2009 ANSYS. Inc. and its subsidiaries and affiliates. Inc. For details.75. CFX Best Practices Guide for Turbomachinery Turbomachinery applications can generally be divided into three main categories: gas compressors and turbines.Chapter 11. A recommended value is 0. and may allow you to restart a multi-stage problem with a better initial guess. If you have trouble converging a problem with many stages. 117) Convergence Tips (p. you may find that solving for a reduced number of stages can give you a better understanding of the physics. Inc. 117) Post-Processing (p. A common boundary condition configuration is to specify the total pressure and total temperature at the inlet and the mass flow at the outlet. If you have trouble converging a simulation involving real gases. try to obtain a solution first using an ideal gas. 121) This guide is part of a series that provides advice for using CFX in specific engineering application areas. and can be modeled by using the Total Energy heat transfer model and enabling the Viscous Work Term option in CFX-Pre. Other configurations are also commonly used.2⁄ ω. 99) in the ANSYS CFX-Solver Modeling Guide. 118) Fans and Blowers (p. liquid pumps and turbines. Each category is discussed in a separate section below. you may find that the problem converges more quickly when a specified blend factor is used instead of a second order high resolution advection scheme. You can also try ramping up boundary conditions and the RPM. Contains proprietary and confidential information of ANSYS. which adds 75% of the second order correction to the upwind advection scheme. where ω is the angular velocity of the rotating domain in radians per second. All rights reserved. The industry-standard k − ω turbulence model is widely used. Ideal gases are available in the real gas library. ensure a resolution of the boundary layer of more than 10 points. 118) Setup for Simulations of Gas Compressors and Turbines Heat transfer and viscous work are involved. 120) Domain Interface Setup (p.1 . A good estimate of the timestep is within the region 0. and its subsidiaries and affiliates. resulting in possible solver failure. It is aimed at users with moderate or little experience using CFX for applications involving turbomachinery. When using the Shear Stress Transport model.© 2009 ANSYS. Selecting an automatic timestep will result in a timestep of 0. see The k-omega and SST Models (p. Inc.1⁄ ω to 1⁄ ω. The second-order high-resolution advection scheme is generally recommended. and fans and blowers. A suggested workaround to this problem is to run the simulation using a static pressure outlet. For lower Mach number cases. the flow can “choke” when the velocity approaches Mach 1. 117 . 119) Frame Change Models (p. Gas Compressors and Turbines This section describes: • • • Setup for Simulations of Gas Compressors and Turbines (p. Convergence Tips For high speed compressors where a specified mass flow outlet boundary condition is applied. This guide describes best practices for setting up simulations involving: • • • • • Gas Compressors and Turbines (p. Release 12. 117) Liquid Pumps and Turbines (p. which is more stable. and the Shear Stress Transport model is also a good choice for these cases. including turbo-specific plots and performance calculation macros. 117). see Liquid Pumps and Turbines (p.1 . All rights reserved. If a total pressure inlet boundary condition is used (recommended).© 2009 ANSYS. 118). it will also provide a useful starting point for streamlines that are colored by total pressure during post-processing. see Convergence Tips (p. To use many of the Turbo Post tools. The optimal performance characteristics can be determined by creating a curve of pressure ratio versus flow rate. a mass flow rate specified outlet is better than a pressure specified outlet. For details.1. “Flow Rate vs Pressure Rise for a Gas Compressor” (p. Region 1 shows an area where a large change in mass flow rate represents a small change in pressure rise. . and efficiency.1. CFD-Post provides a performance macro for gas compressors and turbines. head and flow coefficients. Inc. and a pressure-specified outlet is the best choice. The macro prints a report in HTML showing a number of calculated variables. 119) Convergence Tips (p. which is based on the Perl language. For details. blade loading.Post-Processing Low pressure ratio Gas compressors (1. and its subsidiaries and affiliates. The uniform total pressure distribution means lines will begin with a uniform color.1 or less) can be treated more like liquid pumps. When modeling flow in this region. The Turbo Calculator from the Turbo menu in CFD-Post allows you to perform calculations on the type of application you are modeling. Flow Rate vs Pressure Rise for a Gas Compressor In Figure 11. 118). Post-Processing CFD-Post offers a powerful array of post-processing tools for turbomachinery applications. Inc. 119) Post-Processing (p. This region is close to “choking”. Figure 11. Liquid Pumps and Turbines This section describes: • • • Setup for Simulations of Liquid Pumps and Turbines (p. 119) Release 12. Region 2 shows an area where a small change in flow rate represents a large pressure variation. you must first initialize each domain by specifying the locations of turbo regions and instancing information. You can also create your own macros to customize post-processing using Power Syntax. including torque. 118 Contains proprietary and confidential information of ANSYS. It may be harder to visually resolve these pressure values if an inlet velocity profile is used. The high-resolution advection scheme is recommended. 119) Post-Processing (p. It may be harder to visually resolve these pressure values if an inlet velocity profile is used. The outlet pressure in this case is fairly arbitrary and is usually set at. Contains proprietary and confidential information of ANSYS. the length of the inlet and exit sections can be an important factor when choosing whether to implement the model. Fans and Blowers This section describes: • • • Setup for Simulations of Fans and Blowers (p. Selecting an automatic timestep will result in a timestep of 0. The alternate rotation Release 12. The k − ε or SST model is used to model turbulence. where ω is the angular velocity of the rotating domain in radians per second.© 2009 ANSYS. When setting boundary conditions. The total pressure inlet condition is often more appropriate than the uniform velocity or massflow inlet condition for cases that assume that the machine is drawing fluid directly from a static reservoir. see The k-epsilon Model (p. it will also provide a useful starting point for streamlines that are colored by total pressure during post-processing. or close to zero to reduce round-off error. a good estimate of the timestep is within the region 0. 120) Setup for Simulations of Fans and Blowers Fans and blowers behave like liquid pumps. For details. The fluid is typically air as a general fluid or as an ideal gas at a specified temperature. Where long axisymmetric inlets exist. 119 . but cavitation may be present. For advice on how to deal with cavitation. However. it may be helpful to first run with a specified mass flow inlet and a static pressure outlet.1 . Hence. The specification of a mass flow inlet may be more robust. a total pressure specified inlet and a mass flow outlet are a recommended practice. it can reduce numerical error in such inlet sections. Convergence Tips When only a poor initial guess is available. 119) Convergence Tips (p. and its subsidiaries and affiliates. Post-Processing If a total pressure inlet boundary condition is used (recommended where possible). Boundary conditions. the absolute frame velocity has less swirl than the relative frame velocity. The uniform total pressure distribution means lines will begin with a uniform color. Once the overall flow is established. so the heat transfer option can be set to None in CFX-Pre. This document deals with obtaining solutions for cases without cavitation. 101). see CFX Best Practices Guide for Cavitation (p. The model may introduce errors in the exit stream if the flow is highly swirling. All rights reserved. turbulence models and choice of timestep are the same as for liquid pumps and turbines. Inc. and require a similar model setup. ensure a resolution of the boundary layer of more than 10 points. The k − ε and Shear Stress Transport models are appropriate choices for modeling turbulence. 98) in the ANSYS CFX-Solver Modeling Guide. The flow is generally modeled as incompressible and isothermal. the boundary conditions may then be changed to total pressure at the inlet and mass flow at the outlet. When using the Shear Stress Transport model. CFD-Post provides a performance macro for liquid pumps and turbines.2⁄ ω.1⁄ ω to 1⁄ ω. Convergence Tips The use of the alternate rotation model is an important consideration when modeling fans and blowers.Setup for Simulations of Liquid Pumps and Turbines Setup for Simulations of Liquid Pumps and Turbines Heat transfer is not significant in most cases. Inc. a mass flow inlet assumes a uniform inlet velocity which may not be appropriate. As with gas compressors. Because the alternate rotation model solves for the absolute frame velocity. The Frozen Rotor model must be used for non-axisymmetric flow domains. and being well suited for high blade counts. Inc. The drawbacks of the model include inadequate prediction of physics for local flow values and sensitivity of the results to the relative position of the rotor and stator for tightly coupled components. Usually. Air foil drag is significant and boundary layer friction is an important modeling issue for fans and blowers. See the following figure for a plot of flow rate vs pressure rise for a blower.Post-Processing model is generally recommended. especially for axial fans. 120) Stage (p. The Shear Stress Transport model can provide relatively accurate results where the boundary layer is sufficiently resolved by the mesh. A good resolution of the boundary layer.© 2009 ANSYS. 119). using less computer resources than the other frame change models. periodicity is used to reduce the number of components to a subset that has approximately the same pitch ratio as the full geometry. In most realistic flow situations. is therefore important. The Frozen Rotor model has the advantages of being robust. Frame Change Models When specifying domain interfaces in CFX-Pre. propeller/ship and scroll/volute cases. and its subsidiaries and affiliates. such as impeller/volute. It can also be used for axial compressors and turbines. Post-Processing A similar postprocessing approach to pumps and turbines is also useful for fans and blowers. 121) Transient Rotor-Stator (p. this model reduces (or at least will not increase) numerical errors. The choices are: • • • Frozen Rotor (p. the flow passing through the interface is scaled according to the net pitch ratio of the subsets. you must select the type of analysis that will be carried out in the solver. To account for differences in pitch ratio between the subset and the full geometry. Release 12. 121) Frozen Rotor The Frozen Rotor model treats the flow from one component to the next by changing the frame of reference while maintaining the relative position of the components.1 . see Post-Processing (p. For details. . requiring a high concentration of nodes close to the blade surfaces. turbine/draft tube. All rights reserved. Inc. 120 Contains proprietary and confidential information of ANSYS. This usually occurs around the cut-off or “tongue” illustrated in the diagram. The model is useful for large pitch ratios and still takes a relatively short time to solve. Contains proprietary and confidential information of ANSYS. 121). This model is robust and yields high accuracy predictions of loading. Element Aspect Ratio at Domain Interface Case 1: Impeller/Volute A basic impeller/volute sketch is shown in Figure 11. A sliding interface is used to allow a smooth rotation between components. Transient Rotor-Stator The Transient Rotor-Stator model takes into account all of the transient flow characteristics. the Transient Rotor-Stator model scales the flow from one component to the next in order to account for a non-unity net pitch ratio. The model is not suitable for applications with tight coupling of components and/or significant wake interaction effects and may not accurately predict loading. A good practice here is to create the domain interface halfway across the narrowest gap between the blade and volute wall.1:1 and 10:1. as measured by x/y in Figure 11. “Impeller/Volute” (p. compressors and pumps. Possible applications include axial turbines. 121 . Figure 11. General Considerations • • • Domain interfaces should typically be placed midway between the rotor and stator for turbomachinery cases. Domain Interface Setup The setup of domain interfaces is an important consideration when defining a problem. The following section outlines some approved practices for use in turbomachinery applications. 122). To avoid numerical errors.1 .© 2009 ANSYS. as well as fans and torque converters. they must be axisymmetric in shape as shown in Figure 11. and its subsidiaries and affiliates. Where circular domain interfaces exist. The drawbacks include high computational cost and large amounts of storage required to hold the transient data. The edge of the inner circle shows the maximum extent of the impeller blades.2. 122).3. “Element Aspect Ratio at Domain Interface” (p. As with the Frozen Rotor model.2. the aspect ratio of elements on the domain interface should be between 0. Inc. “Impeller/Volute” (p.Stage Stage The Stage model circumferentially averages the fluxes in bands and transmits the average fluxes to the downstream component. All rights reserved.3. Inc. Release 12. at position 2 or position 3.5. in the case of a stage interface. 123) shows a blade which extends to the edge of the rotating domain. Although it is convenient to place a domain interface at the blade edge (1).© 2009 ANSYS.Case 2: Step Change Between Rotor and Stator Figure 11. A better alternative may be to use a domain interface upstream or downstream of the step change. Impeller/Volute Case 2: Step Change Between Rotor and Stator For the case shown.4. and (4). (3).) A better arrangement is to extend the rotating domain away from the blade edge. since the non-overlap regions of the interface should be specified as walls. there is a step change in the passage height between the rotor and stator. Figure 11. Inc. should be taken with this setup. the wake would be mixed out at the trailing edge.1 . Release 12. however. All rights reserved. Possible Domain Interface Positions with Step Change in Passage Height Case 3: Blade Passage at or Close to the Edge of a Domain Figure 11. 122 Contains proprietary and confidential information of ANSYS. A common choice for placement of the interface would be choice 1. and its subsidiaries and affiliates. . Care. Inc.3. Also. this can result in unrealistic results (The area of the interface would be reduced on one side where the interface is displaced by the blade edge. “Radial Compressor” (p. resulting in an inaccurate pitch change calculation. Domain Interfaces can then be created at (2). you can use two domain interfaces (at positions 1 and 2).© 2009 ANSYS. Inc. Contains proprietary and confidential information of ANSYS. Radial Compressor Case 4: Impeller Leakage A close-up view of part of Figure 11.5. which models flow leaking from a volute back into the impeller region. and its subsidiaries and affiliates. To model the feature. 123 . All rights reserved.5.1 . Inc. Release 12.Case 4: Impeller Leakage Figure 11. “Radial Compressor” (p. 123). or a single domain interface downstream of the leak (position 3). as shown. As an example. Inc. “Domain Interface Between Blade Rows in an Axial Machine” (p.7. In this case. should be located to the right of this region.© 2009 ANSYS.6. . Flow Leakage Through Gap Near Impeller Inlet Case 5: Domain Interface Near Zone of Reversed Flow Be wary of flow moving backwards across stage or frozen rotor interfaces.1 .Case 5: Domain Interface Near Zone of Reversed Flow Figure 11. 124 Contains proprietary and confidential information of ANSYS. shown as a dashed line. The flow moves from left to right everywhere except in a small region just downstream of the trailing edge of the first row of blades. Try relocating the interface to prevent this from occurring. Inc. All rights reserved. Because of the approximations implied by these interfaces. Release 12. the domain interface. and its subsidiaries and affiliates. flow moving upstream and downstream on the same interface will lead to unphysical results. 125) shows two blade rows of an axial machine with a frozen rotor interface between them. Figure 11. © 2009 ANSYS. Contains proprietary and confidential information of ANSYS.Case 5: Domain Interface Near Zone of Reversed Flow Figure 11.7. 125 .1 . Domain Interface Between Blade Rows in an Axial Machine Release 12. All rights reserved. Inc. and its subsidiaries and affiliates. Inc. All rights reserved.© 2009 ANSYS. Contains proprietary and confidential information of ANSYS.1 . and its subsidiaries and affiliates. Inc.Release 12. Inc. . 0. and custom macros (subroutines). see Object Creation and Deletion (p. 129) Parameters (p. 129) Escape Character (p. and its subsidiaries and affiliates. 213). You can view and modify the CCL in these files by using a text editor. Inc. 127 . Power Syntax enables you to embed Perl commands into CCL to achieve powerful quantitative Post-processing.Chapter 12. Contains proprietary and confidential information of ANSYS.1 . 259).5 END • • • • • ISOSURFACE is an object type Iso1 is an object name Variable = Pressure is a parameter Variable is a parameter name Pressure is a parameter value Release 12. All CCL statements can be classified into one of three categories: • • • Object and parameter definitions. 128) Indentation (p. 127) The Data Hierarchy (p. Power Syntax programming. session files can also contain CCL action commands. State files and session files contain object definitions in CCL. For details. ISOSURFACE: Iso1 Variable = Pressure Value = 15000 [Pa] Color = 1. 128) • • • • • • • • • • • Case Sensitivity (p. For more information. which are described in Object Creation and Deletion (p.© 2009 ANSYS. CCL actions. which uses the Perl programming language to allow loops. 128) End of Line Comment Character (p. which are commands that perform a specific task (such as reading a session file) and which are described in Command Actions (p. 213). CFX Command Language (CCL) Syntax The following topics will be discussed: • • • Basic Terminology (p. see Power Syntax in ANSYS CFX (p. 249). 129) Named Objects (p. 129) Lists (p. All rights reserved. logic.0 Transparency = 0. 129) Singleton Objects (p. 131) Basic Terminology The following is an example of a CCL object that defines an isosurface. CFX Command Language (CCL) The CFX Command Language (CCL) is the internal communication and command language of ANSYS CFX. It is a simple language that can be used to create objects or perform actions in the post-processor. 128) Simple Syntax Details (p. In addition. Inc. 129) Parameter Values (p. 128) Continuation Character (p. 128) CCL Names Definition (p. the latter definition overrides the first. Release 12. space or tab. Inc. Mass Flow in). the line does not start with a ! or >). Multiple spaces and tabs appearing inside a name are treated as a single space. and names of parameters all follow the same rules: • • In simple syntax. • Major words start with an upper case letter. numeric.1 . Inc. If data is set in one place and modified in another. objects contain parameters. For simplicity and consistency. provided that the information is set prior to being used further down the file. Case sensitivity is not ideal for typing in many long parameter names. Parameter names. The CFX Expression Language tries to follow the following conventions: 1. CCL Names Definition Names of singletons.The Data Hierarchy • If the object type does not need a name. are mixed case. Materials and Additional Variables) are used to construct corresponding CEL names. The effects of spaces in CCL names are: • • • Spaces appearing before or after a name are not considered to be part of the name. . Only one object of a given singleton type can exist. This is because some names used to define CCL objects (such as Fluids. Single spaces appearing inside a name are significant. a CCL name must be at least one character. but not other objects). This first character must be alphabetic. Any characters may be used within comments. Any text to the right of this character will be treated as comments. Case is preserved for familiar names (for variables k or r). All rights reserved. names of objects. Simple Syntax Details The following applies to any line that is not a Power Syntax or action line (that is. but indentation can be used for easier reading. the following is implemented: • • Singletons and object types use upper case only. types of object. These are grouped into objects that are stored in a tree structure. 128 Contains proprietary and confidential information of ANSYS. and its subsidiaries and affiliates. End of Line Comment Character The # character is used for this. and predefined object names. OBJECT1: object name name1 = value name2 = value END Objects and parameters may be placed in any order. In CFD-Post. The Data Hierarchy Data is entered via parameters. there may be any number of subsequent characters and these can be alphabetic. Case Sensitivity Everything in the file is sensitive to case. User object names conventions can be chosen arbitrarily by you. all object definitions are only one object level deep (that is. 2. Indentation Nothing in the file is sensitive to indentation. but it is essential for bringing the CFX Expression Language (CEL) into CCL. or for abbreviation RNG.© 2009 ANSYS. it is called a singleton object. while minor words such as prepositions and conjunctions are left in lower case (for example. even if it occurs within a simple syntax statement. The object definition is terminated by the string END on a line by itself. Both refer to the same definition of U velocity in the rules file. All rights reserved. Leading and trailing spaces are ignored. The characters such as [. a singleton can appear just once as the child of a parent object. Contains proprietary and confidential information of ANSYS. U Velocity = 1. and should first of all conform to the following definition of allowed String values: String • • Any characters can be used in a parameter value. although a given application is free to subsequently assume a space condensation rule when using the data. and then using the result as part of a parameter or object definition. you do not need to precede these characters with the escape character \ when using them in parameter values). and its subsidiaries and affiliates. Object names must be unique within the given scope. 129 . but if the string is processed as a List or part of a List then the commas may be interpreted as separators (see below under List data types). For example.0 [m/s] may belong to a boundary condition object. such characters terminate the preceding Perl variable name. Subsequent lines may define parameters and child objects associated with this object. Other characters that might be special elsewhere in power syntax are escaped automatically when they appear in parameter values. The appearance of # anywhere in the CCL file denotes the start of a comment.1 . followed by a : and an object name. there may be several instances of a named object of the same type defined with different names. • • • • Some examples of valid parameter values using special characters in power syntax are: Release 12. Following a $.Simple Syntax Details Continuation Character If a line ends with the character \. they are considered part of the value. Inc. ]. Named Objects A named object consists of an object type at the start of a line. There is no restriction on the number of continuation lines. Parameter values can contain commas.{ and } are special only if used in conjunction with $. @. A string beginning with $ is evaluated as a Power Syntax variable. A parameter may belong to many different object types. Parameter Values All parameter values are initially handled as data of type String. However. Internal spaces in parameter values are preserved as given.© 2009 ANSYS. For example. followed by a :. the following line will be linked to the existing line. Singleton Objects A singleton object consists of an object type at the start of a line. Lists Lists are used within the context of parameter values and are comma separated. Parameters A parameter consists of a parameter name at the start of a line followed by an = character followed by a parameter value. and the name must not contain an underscore. % and & are escaped automatically (that is. String values or other parameter type values are normally unquoted. The difference between a singleton object and a named object is that (after the data has been processed). Inc. The object definition is terminated by the string END on a line by itself. Subsequent lines may define parameters and child objects associated with this object. If any quotes are present. The characters $ and # have a special meaning. This is useful for performing more complex Power Syntax variable manipulation.0 [m/s] may belong to an initial value object and U Velocity = 2. If a real is specified when an integer is needed.0 is not supported within CCL and hence within CFD-Post. Release 12. 1 or ON are all equivalent. names = one. all case variants are accepted. fred. separated by commas. NO or FALSE or 0 or OFF are all equivalent. comma separated. the real is rounded to the nearest integer.1 . followed optionally by a dimension. Items in a String List should not contain a comma unless contained between parentheses.2. Units use the same syntax as CEL. Inc. Note that all items in the list must have the same dimensions. One exception can be made if the String List to be is interpreted as a Real List (see below). each item in the String List follows the same rules as String data. three. F are accepted (O is not accepted for On/Off). Expressions are allowed to include commas inside function call argument lists.0 [m/s]. Logical Several forms are acceptable: YES. Logical List List of logicals. 4. two. Integer List List of integers. Real A single-precision real number that may be specified in integer.0 [cm/s] The list syntax 5*2.24 a = 1.24 [m s^-1] A real may also be specified as an expression such as: a = myvel^2 + b a = max(b. All rights reserved. Inc. four Integer Sequence of digits containing no spaces or commas.0 [m/s].0 to represent 5 entries of the value 2.© 2009 ANSYS. or scientific format. TRUE.exe &" Pressure = $myArray[4] Option = $myHash{"foo"} Fuel = C${numberCatoms}H${numberHatoms} Parameter values for data types other than String will additionally conform to one of the following definitions. nO). initial letter variants Y.0*myvel. Otherwise. 3. N. floating point. Logical strings are also case insensitive (YeS. Items that are expressions may include commas inside function call argument lists. and the enclosed commas will be ignored when the list is parsed into individual items. 2. and its subsidiaries and affiliates.0 [m/s]. .0) Real List List of reals. 2. separated by commas.Simple Syntax Details Estimated cost = \$500 Title = Run\#1 Sys Command = "echo 'Starting up Stress solver' . T. String List A list of string items separated by commas. Example usage: a = 1. Example usage: a = 12. 130 Contains proprietary and confidential information of ANSYS.224E01 a = 12. for example. Inc. Contains proprietary and confidential information of ANSYS.1 . Inc.Simple Syntax Details Escape Character The \ character to be used as an escape character.© 2009 ANSYS. All rights reserved. Release 12. to allow $ or # to be used in strings. 131 . and its subsidiaries and affiliates. Contains proprietary and confidential information of ANSYS. Inc. All rights reserved.© 2009 ANSYS.1 . Inc.Release 12. and its subsidiaries and affiliates. . but this is not required. 138) CEL Technical Details (p. Specify complex boundary conditions. However. The simplest type of definition is the dimensionless value. temperature and angle. 133) CEL Operators. CEL can be used to: • • • Define material properties that depend on other variables. 135) CEL Examples (p. All rights reserved. The concept of units is fundamental to the behavior of values and expressions. they must have the same dimension. 140) CEL Fundamentals The following topics will be discussed: • • Values and Expressions (p. Values are dimensional (that is. Expressions can also be functions of other (predefined) expressions: Release 12. time. You can also monitor the value of an expression during the solution using monitor points. it is meaningful to add a quantity in inches to one expressed in meters.743 You can also specify a value with units. but it is not meaningful to add one expressed in kilograms to one in square feet. 133) CFX Expression Language Statements (p. so you should create all expressions for Design Exploration output parameters in CFD-Post. You can use CEL expressions anywhere a value is required for input in ANSYS CFX. Constants. in order to add two quantities together. for example: b = 3. declarative language that has been developed to enable CFX users to enhance their simulations without recourse to writing and linking separate external Fortran routines.© 2009 ANSYS. or they can be used as part of an expression. that is. Important There is some CEL that works elsewhere in ANSYS CFX. you can use an expression to add two values together: <Expr_1> = <Value_1> + <Value_2> In this example. CFX Expression Language (CEL) CFX Expression Language (CEL) is an interpreted. and its subsidiaries and affiliates. Contains proprietary and confidential information of ANSYS.81 [m s^-2] The dimensions of the quantities of interest for CFD calculations can be written in terms of mass. Inc. but not in CFD-Post. This chapter describes: • • • • CEL Fundamentals (p. 134) Values and Expressions CEL can be used to generate both values and expressions.Chapter 13. length. Any expression created in CFX-Pre and used as a Design Exploration output parameter could potentially cause fatal errors during the Design Exploration run. Inc. and Expressions (p. for example: g = 9.1 . For example. Add terms to the solved equations. 133 . with units) or dimensionless constants. you may want to predefine <Value_1> and <Value_2>. Values can be used directly. however. one or more references to mathematical constants or results from mathematical expressions. The statements must conform to a predefined syntax that is similar to Fortran mathematical statements and to C statements for logical expressions. To avoid these ambiguities. you could define a constant. All rights reserved. separated by <= (is less than or equal to). if an expression depends inversely on the square of the x coordinate. * (multiplication). there is no requirement that area names be unique between physics and mesh. CFX Expression Language Statements The CFX Expression Language is declarative. For example. && (logical AND) and || (logical OR). The logical constants are false and true. Results of logical expressions are expressed as 0 and 1 (corresponding to false and true. < (is less than). with optional grouping of these by parentheses. for mathematical expressions. The use of constants may be of benefit in generating complicated expressions or if you have several expressions that use the same constants.CFX Expression Language Statements <Expr_2> = <Expr_1> + <Value_3> Units follow the conventions in the rest of CFX. > (is greater than) and >= (is greater than or equal to) with optional grouping of these by parentheses. Inc. for logical expressions involving relational operators.© 2009 ANSYS. and that any quantity can be defined either in terms of the solution units. ANSYS CFX also has @REGION CEL syntax so that you can identify a named area as being a mesh area. Release 12. Inc. if this is not found. or any other set of units with the correct form. For example. physics areas are boundaries while mesh areas are regions. one or more references to mathematical constants. with optional grouping by parentheses. 134 Contains proprietary and confidential information of ANSYS. for logical expressions involving logical operators. This defines a constant. these will determine the resulting units for the expression. respectively). ANSYS CFX first checks to see if "@<locator>" is a physics name. you could choose to evaluate the expression x + 5 [m]. An expression does not have its own units string. These two types of area can occupy completely different spaces in a simulation. b = 5 [m] and then create an expression x + b. The syntax rules for these expressions are the same as those for conventional arithmetic. but if it references quantities that have dimensions. or existing user variables. • • Use of Constants Constants do not need to be defined prior to being used in an expression. You declare the name and definition of the expression using expression language statements. == (is equal to). The statement must consist of the following: • • a number. system variables. . / (division) and ^ (exponentiation). the name is checked in the list of mesh names. Constants without units are termed dimensionless. This can lead to ambiguities when you use these names in expressions. separated by + (addition). optionally with associated units. Thus if "in1" is both the name of a physics area and the name of a mesh area. one or more references to logical constants or results from relational operations separated by ! (negation).1 . then it has implied dimensions of length to the power -2. Thus to identify the mesh area in1. Or. "@<locator>" is taken to indicate the physics area. in that a calculation has a set of solution units (by default.(subtraction). . and its subsidiaries and affiliates. != (is not equal to). you would use the syntax: @REGION:in1 Note that if <locator> does not appear as a physics name or a mesh name. Using Locators in Expressions A CFX simulation has physics areas and mesh areas. SI units). the expression fails. The precedence of mathematical operators is as follows (from highest to lowest): • • • • The power operator ^ as in x^y. A. that consists of three complex terms.CEL Operators. The logical AND operator (&&) as in x && y. Multiplication and division as in x*y/z. Addition and subtraction as in x+y-z. B. to use more than one line when creating your expression. as of ANSYS CFX 10. 137) Using Expressions (p. logical and operational operators as built-in functions to help you create complex expressions using the Expression details view. The relational operator is equal to and is not equal to (== and !=) as in x != y. Contains proprietary and confidential information of ANSYS. The logical OR operator (||) as in x || y.0. Inc. The unary minus or negation operator . For example. Release 12. it will appear in the Existing Definitions list box as if it were generated on a single line (A + B/C). The relational operators involving less than or greater than (<=. Constants. 136) CEL Constants (p. The precedence of logical and relational operators is as follows (from highest to lowest): • • • • • The negation operator ! as in !x. CEL Operators. the precedence of mathematical operators has been made consistent with standard programming languages such as Fortran and C. and Expressions Expression Syntax All numbers are treated as real numbers. Multiple-Line Expressions It is often useful. You do not need to enter the operator twice.© 2009 ANSYS. 135 . now has the highest precedence. Once the expression has been created. 135) Conditional if Statement (p. you may have an equation. Please note that. Inc. and C. and its subsidiaries and affiliates. All rights reserved. the power operator. <.1 . A + B/C. CFX allows you to use multiple lines to generate an expression. Constants.as in -x. and Expressions The following topics are discussed: • • • • CEL Operators (p. provided each line is separated by an appropriate operator. In this case. particularly with complex expressions. > and >=) as in x >= y. which previously had lower precedence than unary minus. Therefore. you could use three lines to simplify creating the expression: A + B / C Note that the operator may be used at the end of a line (A +) or at the beginning of a line (/ C). 137) CEL Operators CFX provides a range of mathematical. 0. All rights reserved. and its subsidiaries and affiliates. a conditional statement cannot be used to avoid division by zero as in if( x>0.© 2009 ANSYS. expression) Any Dimensionless x>0 [x]^y x^y (if y is not simple Dimensionless & constant) !x x <= y x<y x>y x >= y x == y x != y x && y x || y a Dimensionless x>0 0 or 1 Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Any Any Any Any Any Any Dimensionless Dimensionless [x] [x] [x] [x] [x] [x] Dimensionless Dimensionless 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 For y < 0.1 .0). Inc. Any constant. a division Release 12. . Inc. false_expr ) where: • • • cond_expr: is the logical expression used as the conditional test true_expr: is the mathematical expression used to determine the result if the conditional test is true. integer expression) x^y (if y is any simple. CEL Operators Operator First Operand's Dimensions [x] Any Any Any Any Any [x] [x] Any Any Dimensionless Second Operand's Dimensions [y] Operands' Values Result's (Approx) Dimensions Any Any Any Any [x] [x] [x] [x]*[y] [x]/[y] [x]^y -x x+y x-y x*y x/y y≠0 Anya x^y (if y is a simple. 1. 1/x.1. Note The expressions true_expr and false_expr are always evaluated independent of whether the evaluation of cond_expr is true or false. when x=0. true_expr. 136 Contains proprietary and confidential information of ANSYS. constant.Conditional if Statement Table 13. x must be non-zero. As a consequence. In this case. Conditional if Statement CEL supports the conditional if statement using the following syntax: if( cond_expr. false_expr : is the mathematical expression used to determine the result if the conditional test is false. 02214199E+23 1. CEL Constants Constant R avogadro boltzmann clight e echarge epspermo g mupermo pi planck stefan m s^-2 N A^-2 Dimensionless Js W m^-2 K^-4 Units J K^-1 mol^-1 mol^-1 J K^-1 m s^-1 Dimensionless As Description Universal Gas Constant: 8. CEL Constants Right-click in the Expression details view to access the following useful constants when developing expressions: Table 13.60217653E-19 1. they are converted internally to [K].1 . Inc. Use of Offset Temperature When using temperature values in expressions.15 [K] 0 [C] + 30 [K] 273. any unit conversion will include the offset between temperature scales. a use phase.99792458E+08 Constant: 2.7182817 Constant: 1.CEL Constants by zero will still occur because the expression 1/x is evaluated independent of whether x>0 is satisfied or not./(clight*clight*mupermo) Acceleration due to gravity: 9. The following expression will not produce the expected result: Release 12. 137 . Inc.15 [K] + 30 [K] These are only equivalent because all units are to the power of unity and units other than [K] appear no more than once in each expression. For terms that have temperature to the power of unity. However. and its subsidiaries and affiliates. in all other cases the offset is ignored since this is usually the most appropriate behavior.© 2009 ANSYS.314472 6.2. each of the expressions below is equivalent: Temperature Temperature Temperature Temperature = = = = 30 [C] 303.670400E-08 Using Expressions The interaction with CEL consists of two phases: • • a definition phase. and. it is generally safer to use units of [K] only.3806503E-23 2. All rights reserved. The definition phase consists of creating a set of values and expressions of valid syntax. For example. You should therefore take care when specifying an expression involving non-unit powers of temperature.62606876E-34 5.8066502 4*pi*1. The purpose of the Expression details view is to help you to do this. When units are used that posses an offset (for example. [C]).E-07 Constant: 3. Contains proprietary and confidential information of ANSYS.141592654 6. The first three expressions define constant values that are used in the Visc expression. U a velocity scale. The Visc expression calculates the dynamic viscosity based on the equation for Reynolds number given above.1 .E3 [J kg^-1 K^-1] Thermal Conductivity = 2. are not known. The velocity scale is taken as the inlet velocity. All rights reserved. . Inc. L a length scale and μ the dynamic viscosity. Inc. The LIBRARY section of the CCL (CFX Command Language) file appears as follows: LIBRARY : CEL : EXPRESSIONS : Re = 4. The flow is compressible and therefore the density is variable. 138) Example: Feedback to Control Inlet Temperature (p.29E6 [ ] Vel = 60 [m s^-1] L=1. including the dynamic viscosity. Given this information it is possible to calculate the fluid dynamic viscosity based on the Reynolds number. Release 12. and its subsidiaries and affiliates. 139) Example: Reynolds Number Dependent Viscosity In this example it is assumed that some of the fluid properties.30 [K] because each value is converted to [K] and then summed. 138 Contains proprietary and confidential information of ANSYS.© 2009 ANSYS. The Reynolds number is given by: Re = ρU L μ where ρ is density.896E1 [kg kmol^-1] Dynamic Viscosity = Visc Specific Heat Capacity = 1. The Visc expression can now be used to replace the value of Dynamic Viscosity in the MATERIAL > PROPERTIES section.CEL Examples Temperature = 0 [C] + 30 [C] This is equivalent to 576. The two expression below are equivalent (as expected) because the offset in scales is ignored for non-unit powers of temperature: Specific Heat = 4200 [J kg^-1 C^-1] Specific Heat = 4200 [J kg^-1 K^-1] CEL Examples The following examples are included in this section: • • Example: Reynolds Number Dependent Viscosity (p. However the Reynolds number.044[m] Visc=areaAve(density)@in*Vel*L/Re END END MATERIAL : Air Ideal Gas Option = Pure Substance PROPERTIES : Option = Ideal Gas Molar Mass = 2. the length scale as the inlet width and the density is calculated as the average density over the inlet area. Within the expression the function areaAve(density)@in is used to evaluate the average density at the inlet.52E-2 [W m^-1 K^-1] END END END This shows that four CEL expressions have been created. inlet velocity and a length scale are known. Visupper and Vislower are simply constant values to define temperature and viscosity values.000545 [ N s m^-2 ] # Vis. Inc. When the outlet temperature is less than 325 K. In addition an expression is used to set the dynamic viscosity to be a linear function of temperature. Contains proprietary and confidential information of ANSYS.21E3 [J kg^-1 K^-1] Thermal Conductivity = 5. and its subsidiaries and affiliates.0 [ K ] # Upper temp. Note that the “\” character indicates a line continuation in CCL.Example: Feedback to Control Inlet Temperature Example: Feedback to Control Inlet Temperature In this example a feedback loop is used to control the outlet temperature by varying the temperature at an inlet. Tupper.© 2009 ANSYS. Visupper = 0.999E2 [kg m^-3] Dynamic Viscosity = VisT Specific Heat Capacity = 4.0018 [ N s m^-2 ] # Vis. 139 . The expression VisT produces a linear function for the dynamic viscosity taking a value of Visupper at Tupper and a value of Vislower at Tlower. Temperature Feedback Loop Fluid from a main and a side inlet enter at temperatures of 275 K and 375 K respectively. LIBRARY: MATERIAL: Water at STP Modified Option = Pure Substance PROPERTIES: Option = General Fluid Density = 9.0 [ K ] # Lower temp. The temperature of the fluid entering from the third inlet depends on the outlet temperature. Tlower.69E-1 [W m^-1 K^-1] END # PROPERTIES END # MATERIAL Water at STP Modified CEL: EXPRESSIONS: Tupper = 375. at Tlower VisT = Vislower+(Visupper-Vislower)*(T-Tlower)/ \ (Tupper-Tlower) # Vis. All rights reserved. In this case it is set to a mean value of the two inlet temperatures.-Temp. The expression Tm sets the desired value of the outlet temperature. When the outlet temperature is greater than 325 K. relationship Tm=(Tupper+Tlower)/2 Tout=areaAve(Water at STP Modified. Inc.1 .T)@outlet Tcontrol=Tlower*step((Tout-Tm)/1[K]) \ +Tupper*step((Tm-Tout)/1[K]) END # EXPRESSIONS END # CEL END # LIBRARY The first four expressions. Release 12. To illustrate the example consider the geometry shown below: Figure 13. Tlower = 275. the fluid from the third inlet is set to 275 K.ccl (CFX Command Language) file appears as follows. at Tupper Vislower = 0. the fluid from the third inlet is set to 375 K. The LIBRARY section of the .1. are averted. Compiled languages. 4. From the Details view Color tab. and is equal to Tupper when Tout-Tm is positive. plot the user variable on a surface or a line (just as you would with any other variable). With byte codes. The second example is a variable expression that plots the pressure coefficient variation on a surface or a line: 1. Inc. Click the Variables tab. Create a user variable defined by cpExp. The link between CEL and the CFX-Solver is accomplished through an internal program called genicode.Examples: Using Expressions in ANSYS CFD-Post Tout calculates the outlet temperature using the areaAve function. The names of inlet and outlet boundaries are “inlet” and “outlet”.© 2009 ANSYS. All rights reserved. and the time taken to set up and debug complicated problems reduced considerably. Create these three expressions: RefPressure = 100000 [Pa] dynHead = 0. Click the Expressions tab.5 * areaAve(Density)@inlet * areaAve(Velocity)@inlet^2 cpExp = (Pressure . then right-click in the Expressions area and select New.1 . Tip Alternatively. Examples: Using Expressions in ANSYS CFD-Post The first example is a single-valued expression that calculates the pressure drop through a pipe. 140 Contains proprietary and confidential information of ANSYS. Create a new expression named “dp”: dp = massFlowAve(Pressure)@inlet – massFlowAve(Pressure)@outlet When you click Apply. CEL Technical Details CEL is a byte code compiled language. 2. then right-click and select New. . Interpreted languages are of two types: the fully interpreted languages such as the UNIX C shell. Finally the expression Tcontrol is used to set the temperature of the third inlet. host machines are loaded with a client program (written in a compiled language and compiled for that machine architecture) that interprets the byte stream. Inc. and its subsidiaries and affiliates. for instance in C or Fortran. many of the problems encountered by writing and linking in separate routines. such as Fortran. there is no need to re-link executable programs to perform a different calculation. type the expression in a table cell and prefix with ‘=’ sign. The cell displays the result when you click outside of the cell. The advantage of the byte code is that they can be the same on all host platforms. the value is shown below the editor. 5. and the byte code compiled languages such as CEL. Since the byte codes are interpreted. the outlet temperature is greater than Tm). Two step functions are used so that the temperature is equal to Tlower when Tout-Tm is positive (that is. Furthermore.RefPressure)/dynHead 3. rely on a translation program to convert them into the native machine language of the host platform. Release 12. Select Insert > Location > Line and use the Details view to position the line in the simulation. obviating the need for platform dependent codes. Genicode generates intermediate code from your CEL definitions and writes to a file that is then interpreted by the CFX-Solver during the solution process. 143) Functions Involving Coordinates (p. 141) Quantitative CEL Functions in ANSYS CFX (p. Inc. 145) CEL Functions with Multiphase Flow (p. 145) Quantitative Function List (p.© 2009 ANSYS. and its subsidiaries and affiliates. 146) CEL Mathematical Functions The following mathematical functions are available for use with all CEL expressions. Functions in ANSYS CFX This chapter describes predefined functions in ANSYS CFX: • • • • • CEL Mathematical Functions (p. Contains proprietary and confidential information of ANSYS. All rights reserved. [a] denotes any dimension of the first operand. 141 . Inc. Note In the Function column in the table below.Chapter 14.1 . Release 12. [a] ) mod( [a]. [ ] )b cos( [radians] ) cosh( [ ] ) exp( [ ] ) int([ ])c loge( [ ] )d log10( [ ] )e min( [a]. Standard Mathematical CEL Functions Function abs( [a] ) acos( [ ] ) asin( [ ] ) atan( [ ] )a atan2( [a]. [ ] )b besselY( [ ]. The value of the first dimensionless operand n.5 Dimensionless Dimensionless Dimensionless −1 ≤ x ≤ 1 −1 ≤ x ≤ 1 Any Any 0≤n 0≤n Any Any Any Dimensionless 0<x 0<x Any Any Any Dimensionless Any Any 0≤x Any Any Any atan does not determine the quadrant of the result. . g The nint function requires a dimensionless argument and is defined as: Release 12.© 2009 ANSYS. b Examples: int(1) = 1 int(2. 1. also referred to as the order of the Bessel function.1) = -3 int(-4. y) returns the remainder on dividing x by y.1 . All rights reserved. and its subsidiaries and affiliates. the function is not defined for y = 0.5) = 2 int(-3.1. but atan2 does. Inc.8) = -4 d e ln(x) is valid as an alias for loge(x) log(x) is valid as an alias for log10(x) f mod(x.. [a] )[b] besselJ( [ ]. .. [a] ) max( [a].). Inc.. c The int function truncates the dimensionless argument to its integer part. 142 Contains proprietary and confidential information of ANSYS. 2.CEL Mathematical Functions Table 14. The second argument is a dimensionless real number. must be an integer (n=0. [a] )f nint([ ])g sin( [radians] ) sinh( [ ] ) sqrt( [a] ) step( [ ] ) h tan( [radians] )i tanh( [ ] ) a Operand's Values Any Result's Dimensions [a] Radians Radians Radians Radians Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless [a] [a] [a] Dimensionless Dimensionless Dimensionless [a]^0. 6) = -3 h i step(x) is 0 for negative x.5) if x >= 0 int(x .]<Function>([<Operand>])@<Location> where: • • Terms enclosed in square brackets [ ] are optional and terms in angle brackets < > should be replaced with the required entry. 143 • • • • . For a description of the full CFX Expression Language. For multi-phase cases in CFX-Pre.4) = 2 nint(1) = 1 nint(-1) = -1 nint(-2. For multi-phase cases in CFD-Post. or polydispersed fluid. domain. then the phase name associated with the domain. domain boundary. In CFD-Post. For details. The function can be further qualified by appending _Coordinate_Direction. if the phase name is not specified in the <Operand>.© 2009 ANSYS. if the phase name is not specified then the bulk quantity (if available for the CFX-Solver Results file) is used. Inc. <Coordinate_Direction>: specifies a particular coordinate direction.6) = 3 nint(2. 145). There are some differences between CEL functions in CFX-Pre and CFX-Solver and those in CFD-Post. Examples: nint(2. particle.. see below. Inc. subdomain. . See Coordinate Frame Command (p. if the coordinate frame is not specified then the global frame is used. size group.1 . subdomain. monitor point. and its subsidiaries and affiliates. or comparing values. <Operand>: specifies the argument of the function (if required). All rights reserved. if the coordinate frame is not specified (in _Coordinate_Direction ) then the function will use the coordinate frame associated with the object (such as for a material.5) = 3 nint(2. The phase can be fluid. Quantitative CEL Functions in ANSYS CFX CEL expressions can incorporate specialized functions that are useful in CFD calculations. initialization. where n=1. 130) in the ANSYS CFD-Post User's Guide. 146). x must be dimensionless. 146). The syntax used for calling these functions when used within CEL expressions is: [<Phase_Name>.Quantitative CEL Functions in ANSYS CFX int(x + 0. initialization or function in which the operand is being evaluated will be used.][<Comp_Name>. The operand can be either a valid mathematical CEL expression (only in CFD-Post) or specified using the following general variable syntax: [<Phase_Name>. See Quantitative Function List (p. subtracting. <Component_Name>: specifies a valid name of a component material. a discussion of the handling of the phase name when it is not used to qualify (prepended to) <Function> and/or <Operand> can be found in CEL Functions with Multiphase Flow (p. 3. domain boundary.4) = -2 nint(-2. solid. Important You must use consistent units when adding.5) if x < 0 See the implementation of int( ) function in the table above. In CFX-Pre. or reaction <Function>: specifies the CEL function to evaluate.Difference] Release 12.0.][<Component_Name>. For multi-phase cases in CFX-Pre. The syntax of the coordinate direction is [x|y|z][_<Coordinate_Frame>] where the coordinate frame can be the global coordinate frame or any user defined coordinate frame.5 for x=0. tan(x) is undefined for x=nπ /2. fluid pair.<Var_Operator>][.]<Var_Name>[. 133). <Phase_Name>: specifies a valid name of a phase. see CFX Expression Language (CEL) (p.5) = -3 nint(-2. 1 for positive x and 0. for discussion of creating a coordinate frame in CFD-Post. Contains proprietary and confidential information of ANSYS.. All CEL functions are described in Quantitative Function List (p. 5. reference location or spark ignition object) in which it is being invoked. source point. All but the <Derived> operator are available in CFX-Pre and CFD-Post.theta. a domain boundary. mesh region etc. An exception applies for the position vector x. if the variable name corresponds to that of a component of a vector or a tensor and coordinate frame is not prescribed (as part of the coordinate direction) then the global coordinate frame is used. In CFD-Post.Difference.][REGION:]<Location_Name> The case syntax [Case:<Case_Name>. The <Derived> variable operator is available in CFD-Post. <Location>: specifies the location over which the function is to be applied. see Functions Involving Coordinates (p. you can create an Additional Variable based on any expression and then use the Additional Variable as the operand. Inc. The operand must be valid for the physical models being used over the entire location. and <Variable_Operator>. see Data Acquisition Routines in the ANSYS CFX-Solver Modeling Guide. The syntax of location is: [Case:<Case_Name>. subdomain.1 . In CFX-Pre. For some functions the operand must be left blank as in area()@Inlet. In CFX-Pre the operand cannot be a CEL expression or any operand qualified by <Variable_Operator>. then in CFD-Post the mesh region will appear in CFD-Post as in1 Region. For example. domain. domain or subdomain.Quantitative CEL Functions in ANSYS CFX where <Comp_Name>. The syntax for specifying the variable operator is [Gradient|Curl|Trnav|Trnsdv|Trnmin|Trnmax|Boundcon|<Derived>]. This is useful for specifying a particular component of a vector or tensor. <Variable_Operator> specifies the name of the variable operator. You can use the short or long form for variable names. then the mesh location name must be prepended by REGION:. a point. conservative values will be used even if the Boundcon variable operator is specified. or. The syntax in1 will refer to the domain boundary. if there is both a domain boundary and a mesh region called in1 in the CFX-Solver Results file. z ( or r. difference variables created during case comparison are appended by . for example Absolute Helicity derived for use with Vortex Cores. 103) in the ANSYS CFD-Post User's Guide. If a mesh region is present with the same name as.] is only available in CFD-Post and is used when multiple cases are loaded to indicate the name of the desired case. then the operand cannot be Pressure. • <Variable_Name>: specifies the base name of the variable.© 2009 ANSYS. which are always local. For primitive or composite mesh regions. y. However. If the location name of a mesh region is the same as the name of a named boundary. provided they are available in the CFX-Solver Results file. see Vortex Core Region (p. . The syntax REGION:<Region Name> can also be used in CFD-Post to refer to any mesh region. Inc. 145). For primitive or composite mesh regions. and its subsidiaries and affiliates. In CFX-Pre the variable name can be further qualified by appending _<Coordinate_Direction>. In CFD-Post [<Location_Name>] can be any loaded or user-defined location (for example. if the location spans fluid and solid domains. Release 12. respectively. <Var_Name>. and either of in1 Region or REGION:in1 can be used to refer to the mesh region as desired. <Variable_Name>. then the mesh region is imported into CFD-Post with a Region suffix.z) components. In CFX-Pre [<Location_Name>] must be a domain boundary. In CFX-Pre the variable operator can be further qualified by appending _<Coordinate_Direction>. and <Var_Operator> represent <Component_Name>. plane. For example. primitive or composite mesh region.). for example Velocity_y_myLocalFrame. for example. The operand always uses the conservative values unless the Boundcon variable operator is specified (for details. 144 Contains proprietary and confidential information of ANSYS. All rights reserved. domain boundary. • • Note You cannot use a composite region that consists of a mixture of 2D and 3D regions. see Data Acquisition Routines in the ANSYS CFX-Solver Modeling Guide). conservative values will be used even if the name of the mesh region is the same as that of a named boundary. 2. representing the local coordinates. and its subsidiaries and affiliates. the following is a valid expression definition: z*areaAve(xGlobal)@inlet CEL Functions with Multiphase Flow Note These functions are available in CFX-Pre and CFX-Solver without restrictions. r and theta. If the function is fluid-specific.10000 [Pa])@outlet area_x()@inlet Water at RTP. the solver will stop with an error. All rights reserved. the variables xGlobal. and in CFD-Post with the restriction that you cannot use short names.Functions Involving Coordinates Table 14.1 . See cases 1 to 7 in the table below.force_z()@Default This results in the area-weighted average of pressure on the boundary named Inlet. This syntax is appropriate only for CFD-Post. y. If both the function or operand are fluid-specific. 145 . See case 10 in the table below. See case 8 in the table below. then the fluid specified for the operand will be assumed for the function as well.© 2009 ANSYS. z. Functions Involving Coordinates The CEL variables x. See cases 7 and 9 in the table below. Examples of the Calling Syntax for an Expression areaAve(p)@Inlet area()@REGION:myCompositeMeshRegion areaAve(Pressure . For other fluid-specific functions: • • • if a fluid-specific operand is specified and no fluid is specified for the function. Release 12. Inc. and a phase name is not given for either. For example. cannot be used as the variable. then the bulk mass flows will be used. This results in the area of a 2D mesh region named myCompositeMeshRegion. Contains proprietary and confidential information of ANSYS. if the phase name is not specified for the function. Inc. then the fluid specified for the function will be assumed for the operand as well. yGlobal and zGlobal can be used. if the function is specified and no fluid is specified for the operand. However. various behaviors are possible depending on the function type: • • For massFlow and massFlowAve. Volume Fraction)@domain1 Air. and its subsidiaries and affiliates. CEL Multiphase Examples Case 1 2 3 4 5 6 7 8 9 10 CEL Function .massInt(Volume Fraction)@domain1 massFlowAve(Volume Fraction)@inlet Behavior Bulk mass flow rate through inlet Air mass flow rate through inlet Bulk mass flow averaged pressure on inlet Air mass flow averaged pressure on inlet Bulk mass flow averaged air volume fraction on inlet Air mass flow averaged air volume fraction on inlet Same as Air.Volume Fraction)@ inlet Same as Air.Multiphase massFlow()@inlet Air. . Release 12. Inc.3.massFlowAve(Pressure)@inlet massFlowAve(Air.© 2009 ANSYS. In the table that follows.massFlowAve(Volume Fraction)@inlet massInt(Air. on a boundary the functions use conservative values for the operand unless this is overriden by the Boundcon variable operator in CFX-Pre. on a subdomain the functions use element values for the operand.Volume Fraction)@inlet Air. The behavior of the functions in the table below depends in the type of <Location>. Typically: • • • • on a domain the functions use vertex values for the operand.massFlow()@inlet massFlowAve(Pressure)@inlet Air. in CFX-Pre and CFX-Solver <Expression> means "Additional Variable Expression”.massFlowAve(Air. 146 Contains proprietary and confidential information of ANSYS. Inc.1 . All rights reserved.massFlowAve(Air.Volume Fraction)@ domain1 Error because no fluid specified Quantitative Function List The available quantitative functions are outlined in the sections that follow.massInt(Air.Volume Fraction)@ domain1 Same as Air.Quantitative Function List Table 14. however.massInt(Air. on user locations in CFD-Post the functions use values interpolated from nodal values. <Expression> in CFD-Post means any expression.Volume Fraction)@inlet Air. 150). areaAve_x[_<Coord Frame>]( ) areaAve_y[_<Coord Frame>]( ) areaAve_z[_<Coord Frame>]( ) The (signed) component of the normal area vector CFD-Post weighted average in the local x. Inc. The normal area vectors are always directed out of the domain. The area of a closed surface will always be zero. y or z direction. All The areaInt function projects the location onto a plane normal to the specified direction (if the direction is not set to None) and then performs the calculation on the projected location (the direction specification can also be None). The area of a closed surface will always be zero. Supports @<Location> ave(<Expression>) Arithmetic average of <Expression> over nodes within All a domain or subdomain. 152). Inc. CEL Functions in CFX-Pre/CFX-Solver and in CFD-Post Function Name and Syntax <required> [<optional>] area( ) Operation Area of a boundary or interface. Availability All Release 12. y or z direction. Supports @<Location> See ave (p. 151).Quantitative Function List Table 14. therefore you may obtain positive or negative areas depending on the orientation of your domain and the boundary you are operating on.1 . Supports @<Location> See area (p. 147 . The normal area vectors are always directed out of the domain. Supports @<Location> See areaInt (p. All rights reserved. All Supports @<Location> See areaAve (p. therefore you may obtain positive or negative areas depending on the orientation of your domain and the boundary you are operating on. The area of a closed surface will always be zero. The normal area vectors are always directed out of the domain. areaInt_x[_<Coord Frame>]( ) areaInt_y[_<Coord Frame>]( ) areaInt_z[_<Coord Frame>]( ) The (signed) component of the normal area vector All weighted integral in the local x. Supports @<Location> areaInt(<Expression>) Area-weighted integral of <Expression> on a boundary. The direction of the normal vectors for the location is important and will cancel out for surfaces such as closed surfaces. 151). y or z direction. therefore you may obtain positive or negative areas depending on the orientation of your domain and the boundary you are operating on. area_x[_<Coord Frame>]( ) area_y[_<Coord Frame>]( ) area_z[_<Coord Frame>]( ) The (signed) component of the normal area vector in the Alla local x. and its subsidiaries and affiliates.© 2009 ANSYS.4. Supports @<Location> areaAve(<Expression>) Area-weighted average of <Expression> on a boundary. Contains proprietary and confidential information of ANSYS. Quantitative Function List Function Name and Syntax <required> [<optional>] count( ) Operation Counts the number of evaluation points (nodes) on the named region. See count (p. 153). countTrue(<Expression>) Counts the number of nodes at which the logical expression evaluates to true. Supports @<Location> See countTrue (p. 153). force( ) The magnitude of the force vector on a boundary. Supports [<Phase>.], @<Location> See force (p. 154). forceNorm [_<Axis>[_<Coord Frame>]]( ) The length of the normalized force on a curve in the specified direction. Supports [<Phase>.], @<Location> See forceNorm (p. 155). force_x[_<Coord Frame>]( ) force_y[_<Coord Frame>]( ) force_z[_<Coord Frame>]( ) inside() The (signed) component of the force vector in the local Alla x, y or z direction. Supports [<Phase>.], @<Location> Similar to the subdomain variable, but allows a specific CFX-Pre, CFX-Solver 2D or 3D location to be given. Supports @<Location> See inside (p. 155). length() Length of a curve. Supports @<Location> See length (p. 156). lengthAve(<Expression>) Length-weighted average. Supports @<Location> See lengthAve (p. 156). lengthInt(<Expression>) Length-weighted integration. Supports @<Location> See lengthInt (p. 157). mass() The total mass within a domain or subdomain. This is fluid-dependent. Supports @<Location> See mass (p. 157). massAve(<Expression>) Mass-weighted average of <Expression> on a domain or CFX-Pre, subdomain. CFX-Solver Supports @<Location> See massAve (p. 157). CFX-Pre, CFX-Solver CFD-Post CFD-Post CFD-Post CFD-Post All All Availability All Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 148 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Quantitative Function List Function Name and Syntax <required> [<optional>] massFlow() Operation Mass flow through a boundary. Supports [<Phase>.], @<Location> See massFlow (p. 157). massFlowAve(<var>) Mass flow weighted average of <Expression> on a boundary. Supports [<Phase>.], @<Location> See massFlowAve (p. 158). massFlowAveAbs(<var>) Absolute mass flow weighted average of <Expression> All on a boundary. Supports [<Phase>.], @<Location> See massFlowAveAbs (p. 159). massFlowInt(<var>) Mass flow weighted integration of <Expression> on a boundary. Supports [<Phase>.], @<Location> See massFlowInt (p. 160). massInt(<Expression>) The mass-weighted integration of <Expression> within CFX-Pre, a domain or subdomain. CFX-Solver Supports @<Location> See massInt (p. 161). maxVal(<Expression>) Maximum Value of <Expression> within a domain or subdomain. Supports @<Location> See maxVal (p. 161). minVal(<Expression>) Minimum Value of <Expression> within a domain or subdomain. Supports @<Location> See minVal (p. 161). probe(<Expression>) Returns the value of the specified variable on the specified All Point locator. Supports @<Location> See probe (p. 162). rmsAve(<Expression>) RMS average of <Expression> within a 2D domain. Supports @<Location> See rmsAve (p. 162). sum(<Expression>) Sum of <Expression> over all domain or subdomain vertices. Supports @<Location> See sum (p. 162). All CFX-Pre, CFX-Solver All All All All Availability All Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 149 area Function Name and Syntax <required> [<optional>] torque( ) Operation Magnitude of the torque vector on a boundary. Supports [<Phase>.], @<Location> See torque (p. 163). torque_x[_<Coord Frame>]() torque_y[_<Coord Frame>]() torque_z[_<Coord Frame>]() volume( ) The (signed) components of the torque vector about the CFX-Pre, local x, y, or z coordinate axis. CFX-Solvera Supports [<Phase>.], @<Location> The total volume of a domain or subdomain. Supports @<Location> See volume (p. 163). volumeAve(<Expression>) Volume-weighted average of <var> on a domain. Supports @<Location> See volumeAve (p. 163). volumeInt(<Expression>) Volume-weighted integration of <var> within a domain All or subdomain. Supports @<Location> See volumeInt (p. 164). a Availability All All All See the definition for [_<Coordinate_ Direction>]] in Quantitative CEL Functions in ANSYS CFX (p. 143) area The area function is used to calculate the area of a 2D locator. area[_<Axis>[_<Coord Frame>] ]()@<Location> where: • • • <Axis> is x, y, or z <Coord Frame> is the coordinate frame <Location> is any 2D region (such as a boundary or interface). An error is raised if the location specified is not a 2D object. If an axis is not specified, the total area of the location is calculated. area()@Isosurface1 calculates the total area of the location, and Isosurface1.area_y()@Isosurface1 calculates the projected area of Isosurface1 onto a plane normal to the Y-axis. Tools > Command Editor Example >calculate area, <Location>, [<Axis>] The specification of an axis is optional. If an axis is not specified, the value held in the object will be used. To calculate the total area of the location, the axis specification should be left blank (that is, type a comma after the location specification). >calculate area, myplane calculates the area of the locator myplane projected onto a plane normal to the axis specification in the CALCULATOR object. >calculate area, myplane, calculates the area of the locator myplane. Note that adding the comma after myplane removes the axis specification. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 150 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. areaAve Tools > Function Calculator Example The following example will calculate the total area of the locator Plane1: Function: area, Location: Plane1. areaAve The areaAve function calculates the area-weighted average of an expression on a 2D location. The area-weighted average of a variable is the average value of the variable on a location when the mesh element sizes are taken into account. Without the area weighting function, the average of all the nodal variable values would be biased towards variable values in regions of high mesh density. areaAve[_<Axis>[_<Coord Frame>] ](<Expression>)@<Location> where: • • • • <Axis> is x, y, or z <Coord Frame> is available in CFD-Post only <Expression> is an expression <Location> is any 2D region (such as a boundary or interface). An error is raised if the location specified is not a 2D object. To calculate the pressure coefficient Cp, use: (Pressure - 1[bar])/(0.5*Density*(areaAve(Velocity)@inlet)^2) You can create an expression using this, and then create a user variable using the expression. The user variable can then be plotted on objects like any other variable. Tools > Command Editor Example >calculate areaAve, <Expression>, <Location>, <Axis> Tools > Function Calculator Examples • This example will calculate the average magnitude of Velocity on outlet. Function: areaAve, Location: outlet, Variable: Velocity. Note that flow direction is not considered because the magnitude of a vector quantity at each node is calculated. • You can use the scalar components of Velocity (such as Velocity u) to include a directional sign. This example will calculate the area-weighted average value of Velocity u, with negative values of Velocity u replaced by zero. Note that this is not the average positive value because zero values will contribute to the average. Function: areaAve, Location: outlet, Variable: max(Velocity u, 0.0[m s^-1]). areaInt The areaInt function integrates a variable over the specified 2D location. To perform the integration over the total face area, select the None option from the Axis drop-down menu. If a direction is selected, the result is an integration over the projected area of each face onto a plane normal to that direction. Each point on a location has an associated area which is stored as a vector and therefore has direction. By selecting a direction in the function calculator, you are using only a single component of the vector in the area-weighting function. Because these components can be positive or negative, depending on the direction of the normal on the location, it is possible for areas to cancel out. An example of this would be on a closed surface where the projected area will always be zero (the results returned will not in general be exactly zero because the variable values differ over the closed surface). On a flat surface, the normal vectors always point in the same direction and never cancel out. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 151 ave areaInt[_<Axis>[_<Coord Frame>] ](<Expression>)@<Location> where: • <Axis> is x, y, or z. Axis is optional; if not specified the integration is performed over the total face area. If axis is specified, then the integration is performed over the projected face area. A function description is available. • • <Coord Frame> is the coordinate frame. <Location> is any 2D region (such as a boundary or interface). An error is raised if the location specified is not a 2D object. areaInt_y_Frame2(Pressure)@boundary1 calculates the pressure force acting in the y-direction of the coordinate frame Frame2 on the locator boundary1. This differs from a calculation using the force function, which calculates the total force on a wall boundary (that is, viscous forces on the boundary are included). Tools > Command Editor Example >calculate areaInt, <Expression>, <Location>, [<Axis>] Axis is optional. If it is not specified, the value held in the object will be used. To perform the integration over the total face area, the axis specification should be blank (that is, type a comma after the location name). A function description is available in areaInt (p. 151). Tools > Function Calculator Examples • This example integrates Pressure over Plane 1. The returned result is the total pressure force acting on Plane 1. The magnitude of each area vector is used and so the direction of the vectors is not considered. Function: areaInt, Location: Plane 1, Variable: Pressure, Direction: None • This example integrates Pressure over the projected area of Plane 1 onto a plane normal to the X-axis. The result is the pressure force acting in the X-direction on Plane 1. This differs slightly from using the force function to calculate the X-directional force on Plane 1. The force function includes forces due to the advection of momentum when calculating the force on an internal arbitrary plane or a non-wall boundary (inlets, etc.). Function: areaInt, Location: Plane 1, Variable: Pressure, Direction: Global X. ave The ave function calculates the arithmetic average (the mean value) of a variable or expression on the specified location. This is simply the sum of the values at each node on the location divided by the number of nodes. Results will be biased towards areas of high nodal density on the location. To obtain a mesh independent result, you should use the lengthAve, areaAve, volumeAve or massFlowAve functions. ave(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or a logical expression <Location> is any 3D region (such as a domain or subdomain). The ave function can be used on point, 1D, 2D, and 3D locations. ave(Yplus)@Default calculates the mean Yplus values from each node on the default walls. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 152 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. count Tools > Command Editor Example >calculate ave, <var|Expression>, <Location> Note To obtain a mesh-independent result, you should use the lengthAve, areaAve, volumeAve or massFlowAve functions. The average of a vector value is calculated as an average of its magnitudes, not the magnitude of component averages. As an example, for velocity: v ave = v1 + v 2 2 (Eq. 14.1) where vi = (vx2, i + v 2, i + vz2, i) y (Eq. 14.2) Tools > Function Calculator Example This example calculates the mean temperature at all nodes in the selected domain. Function: ave, Location: MainDomain, Variable: Temperature. count The count function returns the number of nodes on the specified location. count()@<Location> where: • <Location> is valid for point, 1D, 2D, and 3D locations. count()@Polyline1 returns the number of points on the specified polyline locator. Tools > Command Editor Example >calculate count, <Location> Tools > Function Calculator Example This example returns the number of nodes in the specified domain. Function: count, Location: MainDomain. countTrue The countTrue function returns the number of mesh nodes on the specified region that evaluate to “true”, where true means greater than or equal to 0.5. The countTrue function is valid for 1D, 2D, and 3D locations. countTrue(<Expression>)@<Location> where <Expression> is: • • In CFD-Post, an expression that contains the logical operators =, >, <, <=, or >=. In CFX-Solver, an Additional Variable that you define. For example: TemperatureLE = Temperature > 300[K] countTrue(TemperatureLE)@Polyline1 returns the number of nodes on the specified polyline locator that evaluate to true. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 153 force This function returns the force exerted by the fluid on the specified 2D locator in the specified direction. the force is equal to the pressure force plus the mass flow force (due to the advection of momentum). Water at RTP. Expression: Temperature > 300[K]. It is important to note that forces arising as a result of the reference pressure are not included in the force calculation. These quantities are not influenced by any rotation that might occur during a transient run or when a rotational offset is specified. Function: countTrue. the force is equal to the pressure force. For details. if it is available.] is an optional prefix that is not required for single-phase flows. the only difference is in the viscous forces (on wall boundaries) or the mass flow forces. Force calculations on boundaries require additional momentum flow data. It is also important to note that for rotating domains in a transient run. if wall shear data exists in the results file. .1 . the viscous force is added to the calculated force. results for rotating domains in a transient run may be in the rotated position (depending on the setting of Options in CFD-Post) when they are loaded into CFD-Post for post-processing. [<Phase>.force Tools > Command Editor Examples In CFD-Post: >calculate countTrue(Temperature > 300[K]). or z <Coord Frame> is the coordinate frame <Location> is any 2D region (such as a boundary or interface). indicating the direction of the force. CFD-Post calculates the approximate force as follows: • • • If the locator is a wall boundary. Release 12. Inc. <Axis> is x. y. The force function enables you to select the fluids to use when performing your calculation. Inc. see CEL Functions with Multiphase Flow (p. For non-boundary locators. Because the pressure force is the same at each node irrespective of the choice of fluids. The result returned is the force on the locator due to that fluid/those fluids. In all cases. Domain1 In CFX-Solver: >calculate countTrue(TemperatureLE). and its subsidiaries and affiliates. All rights reserved. Location: MainDomain. an approximate force is always calculated. 145). The result can be positive or negative. The force on a boundary is calculated using momentum flow data from the results file.© 2009 ANSYS.]force[_<Axis>[_<Coord Frame>] ]()@<Location> where: • • • • [<Phase>.force_x()@wall1 returns the total force in the x-direction acting on wall1 due to the fluid Water at RTP. For all other locators. 154 Contains proprietary and confidential information of ANSYS. However. Domain1 Tools > Function Calculator Example This example returns the number of nodes that evaluate to “true” in the specified domain. forces on wall boundaries in the CFX-Solver are evaluated in the reference frame fixed to the initial domain orientation. You can include reference pressure effects in the force calculation in the CFX-Solver by setting the expert parameter include pref in forces = t. Function: force. if the polyline were 2D with a width of one unit. <Location> can also be an immersed solid domain on which the expression is evaluated dynamically. see CEL Functions with Multiphase Flow (p. For details. Release 12. but can be any 2D or 3D named sub-region of the physical location on which the expression is evaluated. Direction: Global X.© 2009 ANSYS. forceNorm_y()@Polyline1 calculates the per unit width force in the y-direction on the selected polyline. Phase: All Fluids. and its subsidiaries and affiliates. For immersed solids simulations.1 . 273 [K] * inside()@Subdomain 1 has a value of 273 [K] at points in Subdomain 1 and 0 [K] elsewhere. Location: Polyline1. Phase: Water at RTP. • This calculates the forces on inlet1 due to pressure and the advection of momentum. Location: Default. Momentum data must also be available. This is useful for describing different initial values or fluid properties in different regions of the domain. but allows a specific 2D or 3D location to be given. Pressure and viscous forces are included. y. Function: forceNorm. defined to be unity within a subdomain and zero elsewhere. <Axis> is x. The magnitude of the value returned can be thought of as the force in the specified direction on a polyline. Tools > Command Editor Example >calculate forceNorm. <Axis>. Function: force. Phase: All Fluids. An error will be raised if the location specified is not one-dimensional. the location can also be a specific immersed solid domain. <Axis>. Inc. 155 . Direction: Global X. 145). Location: inlet1. It is similar to the CEL subdomain variable. or z <Coord Frame> is available in CFD-Post only <Location> is any 1D location. [<Phase>. Direction: Global X. [<Phase>] Tools > Function Calculator Example The result from this calculation is force per unit width on Polyline1 in the x-direction. forceNorm Returns the per unit width force on a line in the direction of the specified axis. and the inside function will be updated automatically at the beginning of each time step. inside()@<Location> where: • • <Location> is any 2D or 3D named sub-region of the physical location on which the expression is evaluated.]forceNorm[_<Axis>[_<Coord Frame>] ]()@<Location> where: • • • • [<Phase>. <Location>. [<Phase>] Tools > Function Calculator Examples • This calculates the total force on the default wall boundaries in the x-direction. It is available only for a polyline created by intersecting a locator on a boundary. <Location>. inside The inside CEL function is essentially a step function variable. Contains proprietary and confidential information of ANSYS.] is an optional prefix that is not required for single-phase flows. The location does not need to be a subdomain.forceNorm Tools > Command Editor Example >calculate force. All rights reserved. Inc. For example. Specifying a 2D location will not produce an error.© 2009 ANSYS. Tools > Command Editor Example >calculate lengthAve. Inc. .1 . <Location> Note While using this function in Power Syntax. This is the 1D equivalent of the areaAve function. Function: length. and its subsidiaries and affiliates. Inc. Release 12. Location: Polyline1. The results is independent of the nodal distribution along the line because a weighting function assigns a higher weighting to areas of sparse nodal density. Variable: Velocity. <Location> length Computes the length of the specified line as the sum of the distances between the points making up the line. lengthAve(T)@Polyline1 calculates the average temperature on Polyline1 weighted by the distance between each point (T is the system variable for temperature). Tools > Command Editor Example >calculate length. <Location> Tools > Function Calculator Example This calculates the average velocity on the location Polyline1 using a length-based weighting function to account for the distribution of points along the line. All rights reserved. the sum of the edge lengths from the elements in the locator will be returned. lengthAve(<Expression>)@<Location> where: • • <Expression> is an expression <Location> is any 1D or 2D location. Tools > Command Editor Example >calculate inside. Location: Polyline1. 156 Contains proprietary and confidential information of ANSYS. <Expression>. Tools > Function Calculator Example This example calculates the length of a polyline.length Note The inside CEL function is not available in CFD-Post. lengthAve Computes the length-based average of the variable on the specified line. length()@Polyline1 returns the length of the polyline. length()@<Location> where: • <Location> is any 1D location. the leading character is capitalized to avoid confusion with the Perl internal command “length”. Function: lengthAve. if it is available. 157 . <Location> is any fluid surfaces (such as Inlets. and its subsidiaries and affiliates. <Location>. lengthInt(<Expression>)@<Location> where: • • <Expression> is an expression <Location> is any 1D location. massFlow Computes the mass flow through the specified 2D location. This is the 1D equivalent of the areaInt function. <Location>. All rights reserved. <Expression>. For details. Tools > Command Editor Example >calculate lengthInt. Air at STP. Outlets. an approximate mass flow is calculated. For boundary locators: • The mass flow is calculated using mass flow data from the results file. Inc. see CEL Functions with Multiphase Flow (p. Otherwise. Tools > Command Editor Example >calculate massAve.1 . Release 12.]massFlow()@<Location> where: • • [<Phase>. <Location>. mass mass()@<Location> where: • <Location> is any 3D region (such as a domain or subdomain).© 2009 ANSYS. Openings and fluid-fluid interfaces).lengthInt lengthInt Computes the length-based integral of the variable on the specified line. Inc. 145). <var>. Contains proprietary and confidential information of ANSYS. Tools > Command Editor Example >calculate mass. massAve massAve(<var>)@<Location> where: • • <var> is a variable <Location> is any 3D region (such as a domain or subdomain).massFlow()@DegassingOutlet calculates the mass flow of Air at STP through the selected location.] is an optional prefix that is not required for single-phase flows. [<Phase>. the mass flow through a boundary on a GGI interface evaluated in CFD-Post is an approximation to the 'exact' mass flow evaluated by the solver. For non-boundary locators (that is. In such cases.© 2009 ANSYS. Inc. For details. Inc. Phase: All Fluids. If the locator is an edge based locator (such as a cut plane or isosurface). Location: outlet2. 145). Openings and fluid-fluid interfaces). Each summation term is evaluated on. a node on the 2D locator. see CEL Functions with Multiphase Flow (p. the denominator of the averaging formula becomes small. the massFlowAveAbs (see massFlowAveAbs (p. the domain mass flow data from the results file will be used. All rights reserved. massFlowAve Computes the average of a variable/expression on the specified 2D location. the mass flow is positive at an inlet boundary with the velocity directed into the domain. Mass Flow Sign Convention The mass flow through a surface is defined by − ρV ⋅ n where V is the velocity vector and n is the surface normal vector. the normal of the plane or surface is determined by from the right-hand rule and the manner in which the plane or surface is constructed. . The result returned is the average variable value. Outlets. and corresponds to. The massFlowAve function allows you to select the fluids to use when performing your calculation. Tools > Command Editor Example >calculate massFlow. Therefore. an approximate mass flow is calculated. This approximation vanishes as the mesh is refined or as the volume fraction on the interface becomes uniform. the surface normal at a domain boundary is directed out of the domain. Release 12. massFlowAve(Density)@Plane1 calculates the average density on Plane1 weighted by the mass flow at each point on the location. the surface normal for a Z-X plane has the same sense and direction as the Y-axis.3) where Φ represents the variable/expression being averaged and m represents the local mass flow (net local mass flow if more than one fluid is selected). and its subsidiaries and affiliates. By convention. As a result. For planes and surfaces that cut through a domain. <Location>. the denominator evaluates to the conservative net mass flow through the 2D locator. internal locators): • • The massFlow function enables you to select the fluids to use when performing your calculation. The result returned is the mass flow of the selected fluids through the locator. [<Phase>] Tools > Function Calculator Example This calculates the mass flow for all fluids in the domains through the location outlet2: Function: massFlow.] is an optional prefix that is not required for single-phase flows.massFlowAve • For multiphase cases. [<Phase>. In cases where there is significant flow. and the resulting average value may become adversely affected. An error is raised if the location specified is not 2D. In all other cases. For example. evaluated according to the formula: massFlowAve (Φ ) = Σ (m Φ) Σm (Eq. 159)) function is a viable alternative to the massFlowAve function. but little or no net flow through the 2D locator (as can happen with recirculation).1 . <var|Expression> is a variable or expression <Location> is any fluid surfaces (such as Inlets. 158 Contains proprietary and confidential information of ANSYS. The mass flow for each term is derived from summing contributions from the surrounding solver integration points. 14.]massFlowAve(<var|Expression>)@<Location> where: • • • [<Phase>. CFD-Post uses the integration point mass flow data if it is available. see CEL Functions with Multiphase Flow (p. [<Phase>] Tools > Function Calculator Example This example calculates the average velocity on Plane1 weighted by the mass flow for all fluids assigned to each point on Plane1: Function: massFlowAve. If there is any backflow through the 2D locator. only when all of the flow passes through the 2D locator in the same general direction (in other words. <var|Expression> is a variable or expression <Location> is any fluid surfaces (such as Inlets. Outlets. but little or no net flow through the 2D locator (as can happen with recirculation). even though there may be no actual backflow (as evidenced by a vector plot on the locator). and that the denominator evaluates to the net mass flow through the 2D locator. if available). the massFlowAveAbs function is a viable alternative to the massFlowAve function (see massFlowAve (p. 159) sections under massFlowAveAbs (p. That is: massFlowAveAbs (Φ ) = Σ ( m Φ) Σ m (Eq.4) [<Phase>. <Location>. 159 . Tools > Command Editor Example >calculate massFlowAve. Release 12. backflow through the 2D locator may occur as an artifact of how the mass flow data is applied to the locator nodes. 159) and Mass Flow Technical Note (p. The values of variables other than mass flow are stored at the mesh nodes and are applied to the locator nodes by linear interpolation. except that each local mass flow value used in the averaging formula has the absolute function applied. Phase: All Fluids massFlowAveAbs This function is similar to the massFlowAve function (see massFlowAve (p. otherwise. it will approximate mass flow values based on mesh node values of velocity (and density. For the mass flow variable. when there is no backflow).massFlowAveAbs See the Advanced Mass Flow Considerations (p. Location: Plane1. 159) for more information. In cases where there is significant flow. massFlowAve(Density)@Plane1 calculates the average density on Plane1 weighted by the mass flow at each point on the location. 14. Openings and fluid-fluid interfaces). 158)). An error is raised if the location specified is not 2D. The figure below illustrates how this may occur. Mass Flow Technical Note When integration point mass flow data is stored.1 . Variable: Velocity. Inc. Advanced Mass Flow Considerations Note that the massFlowAveAbs and massFlowAve functions provide the same result. All rights reserved.© 2009 ANSYS. Contains proprietary and confidential information of ANSYS. Inc. the denominator in the function for massFlowAveAbs evaluates to a value of greater magnitude than the conservative net mass flow through the 2D locator (although this is not necessarily harmful to the resulting average value). 158)).] is an optional prefix that is not required for single-phase flows. and its subsidiaries and affiliates. For details.]massFlowAveAbs(<var|Expression>)@<Location> where: • • • [<Phase>. 145). <var|Expression>. All rights reserved.]massFlowInt(<var|Expression>)@<Location> where: • • • [<Phase>. see CEL Functions with Multiphase Flow (p. massFlowInt Integrates a variable over the specified 2D location.© 2009 ANSYS. <var|Expression> is a variable or expression <Location> is any fluid surfaces (such as Inlets. A weighting function is applied to the variable value at each point based on the mass flow assigned to that point. Openings and fluid-fluid interfaces). try making a contour plot of the variable Mass Flow. This visualization technique works because the method of applying integration-point mass-flow data to locator nodes is the same for all uses of the mass flow variable involving a 2D locator (contour plots. 160 Contains proprietary and confidential information of ANSYS. massFlowAve. and its subsidiaries and affiliates. This will produce a contour plot with two color bands: one for each general flow direction.). Outlets. Inc. [<Phase>.] is an optional prefix that is not required for single-phase flows.1 . etc. For details. setting a user defined Range from 0 to 1 and the # of Contours to 3. You can also specify the fluid(s) used to calculate the mass flow at each locator point.massFlowInt Figure 14. Backflow In order to visualize this type of backflow through a locator. 145).1. Inc. massFlowAveAbs. Release 12. An error is raised if the location specified is not 2D. . Tools > Command Editor Example >calculate maxVal. and its subsidiaries and affiliates. minVal(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or expression <Location> in CFX-Solver is any 2D or 3D region (such as a domain or subdomain). You should create a User Variable if you want to find the maximum value of an expression. Point and 1D. Inc. Location: Plane1.massInt Tools > Command Editor Example >calculate massFlowInt. Variable: Pressure. in CFD-Post.1 . Variable: Yplus minVal Returns the minimum value of the specified variable on the specified locator. in CFD-Post. massInt(<var|Expression>)@<Location> where: • • <var> is a variable <Location> is any 3D region (such as a domain or subdomain) Tools > Command Editor Example >calculate massInt. Contains proprietary and confidential information of ANSYS. <Location> maxVal Returns the maximum value of the specified variable on the specified locator. and 3D locators can be specified. 2D. 161 . The result is the pressure force acting on Plane1 weighted by the mass flow assigned to each point on Plane1: Function: massFlowInt. [<Phase>] Tools > Function Calculator Example This example integrates pressure over Plane1. <Location> Tools > Function Calculator Example This will return the maximum Yplus value on the default wall boundaries: Function: maxVal. Release 12. All rights reserved. <Location>. Point and 1D. Phase: All Fluids massInt The mass-weighted integration of a variable within a domain or subdomain. and 3D locators can be specified. maxVal(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or expression <Location> in CFX-Solver is any 2D or 3D region (such as a domain or subdomain). Inc. Location: Default. <var|Expression>. <var|Expression>. <var>. You should create a User Variable if you want to find the minimum value of an expression. 2D.© 2009 ANSYS. <var|Expression>. and its subsidiaries and affiliates. Important This calculation should be performed only for point locators described by single points. All rights reserved. <var>. . 162 Contains proprietary and confidential information of ANSYS. Incorrect solutions will be produced for multiple point locators. Inc. Location: Point1. Release 12. <Location> Tools > Function Calculator Example These settings will return the minimum temperature in the domain: Function: minVal. Location: MainDomain. Point and 1D. rmsAve(<var>)@<Location> where: • • <var> is a variable <Location> is any 2D region (such as a domain or subdomain). <Expression>.© 2009 ANSYS. Inc. Tools > Command Editor Example >calculate rmsAve. sum(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or expression <Location> in CFX-Solver is any 3D region (such as a domain or subdomain).probe Tools > Command Editor Example >calculate minVal. in CFD-Post. 2D. probe(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or expression <Location> is any point object (such as a Source Point or Cartesian Monitor Point).1 . <Location> sum Computes the sum of the specified variable values at each point on the specified location. <Location> Tools > Function Calculator Example This example returns the density value at Point1: Function: probe. Variable: Density rmsAve Returns the RMS average of the specified variable within a domain. and 3D locators can be specified. Tools > Command Editor Example >calculate probe. Variable: Temperature probe Returns the value of the specified variable on the specified Point object. <Axis>. Tools > Command Editor Example >calculate torque. For details.] is an optional prefix that is not required for single-phase flows. Variable: Volume of Finite Volume torque Returns the torque on a 2D locator about the specified axis. Contains proprietary and confidential information of ANSYS. <Axis> is x. Location: Volume1 volumeAve Calculates the volume-weighted average of an expression on a 3D location.1 . Inc. All rights reserved. this sums to the volume of the subdomain: Function: sum. [<Phase>] Tools > Function Calculator Example This example calculates the torque on Plane1 about the z-axis due to all fluids in the domain. <var|Expression>. 163 . Function: torque. The volume-weighted average of a variable is the average value of the variable on a location weighted by Release 12. Phase: All Fluids volume Calculates the volume of a 3D location. Inc.]torque_[<Axis>[_<Coord Frame>] ]()@<Location> where: • • • • [<Phase>. Tools > Command Editor Example >calculate volume. 145).torque Tools > Command Editor Example >calculate sum. Function: volume. For details. <Location>. <Location> Tools > Function Calculator Example This example returns the sum of the finite volumes assigned to each node in the location SubDomain1. If the location specified is not 2D. y. Location: Plane1. <Location> Tools > Function Calculator Example This example returns the sum of the volumes of each mesh element included in the location Volume1. For details. The force calculated during evaluation of the torque function has the same behavior as the force function. or z <Coord Frame> <Location> is any 2D region (such as a wall). see volume (p. 154). You can select the fluids involved in the calculation. [<Phase>.© 2009 ANSYS. see force (p. an error is raised. 163). and its subsidiaries and affiliates. Location: SubDomain1. volume()@<Location> where: • <Location> is any 3D region (such as a domain or subdomain). In this case. An error is raised if the location specified is not a 3D object. Axis: Global Z. see CEL Functions with Multiphase Flow (p. This is the 3D equivalent of the areaAve function. <Location> Tools > Function Calculator Example This example calculates the integral of density (the total mass) in Volume1. volumeAve(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or expression <Location> is any 3D region (such as a domain or subdomain). All rights reserved. Inc. <var|Expression>. Location: Volume1.© 2009 ANSYS. 164 Contains proprietary and confidential information of ANSYS. volumeInt(<var|Expression>)@<Location> where: • • <var|Expression> is a variable or expression <Location> is any 3D region (such as a domain or subdomain). Tools > Command Editor Example >calculate volumeInt. <Location> Tools > Function Calculator Example This example calculates the volume-weighted average value of density in the region enclosed by the location Volume1: Function: volumeAve. An error is raised if the location specified is not a 3D object. Location: Volume1.volumeInt the volume assigned to each point on a location. and its subsidiaries and affiliates. Variable: Density Release 12. This is the 3D equivalent of the areaInt function. Function: volumeInt. Without the volume weighting function. Tools > Command Editor Example >calculate volumeAve.1 . the average of all the nodal variable values would be biased towards values in regions of high mesh density. The following example demonstrates use of the function. <var|Expression>. volumeInt(Density)@StaticMixer will calculate the total fluid mass in the domain StaticMixer. For example. Variable: Density volumeInt Integrates the specified variable over the volume location. . Inc. CFD-Post uses conservative values when the Calculate command is used. the conservative values should normally be used because they are consistent with the discrete solutions obtained by the solver. but the resulting control volume equation solution will not necessarily be the wall velocity. that the velocity is displayed as zero on no-slip walls. The difference between hybrid and conservative values at wall boundaries can be demonstrated using the following figure: Using velocity as an example. although the specified boundary value is used to close boundary fluxes for the boundary control volume. on a no-slip wall. 166) Particle Variables Generated by the Solver (p. 184) Miscellaneous Variables (p. For visualization purposes. By default. are the values obtained from solving the conservation equations for the boundary control volumes. Contains proprietary and confidential information of ANSYS. Inc. and its subsidiaries and affiliates. These values are not necessarily the same as the specified boundary condition values. This ensures. This is especially true when the value of a conservative solution variable (such as pressure or temperature. 165) List of Field Variables (p. 191) Hybrid and Conservative Variable Values The CFX-Solver calculates the solution to your CFD problem using polyhedral finite volumes surrounding the vertices of the underlying mesh elements (hexahedrons. you can select them from the Variables Editor dialog box as described above. pyramids). the velocity value calculated at a mesh node is based upon the ‘average' in the control volume surrounding that node. The specified boundary values are called hybrid values.© 2009 ANSYS. called conservative values. The conservative values are representative of the boundary control volume. CFD-Post uses hybrid values by default for most variables. a numerical approach must be adopted whereby the equations are replaced by algebraic approximations which may be solved using a numerical method. The solution values on the boundary vertices. For example. it is often useful to view the specified boundary condition value for the boundary vertices rather than the conservative values. To obtain solutions for real flows.Chapter 15. Inc. the entire control volume is then assumed to possess that velocity. not the boundary itself. All rights reserved. its surrounding control volume includes an area in the bulk of the fluid (this area is Release 12. Hybrid values are obtained by overwriting the conservative results on the boundary nodes produced by the CFX-Solver with values based on the specified boundary conditions. the wall velocity is used to compute the viscous force for the boundary face of the boundary control volume. prisms. For calculation purposes. for instance) is specified at a particular boundary condition. 165 . Analytical solutions to the Navier-Stokes equations exist for only the simplest of flows under ideal conditions. For quantitative calculations.1 . If you want to use these values in CFD-Post. At a boundary node. tetrahedrons. Variables in ANSYS CFX This chapter describes the variables available in ANSYS CFX: • • • • Hybrid and Conservative Variable Values (p. for example. a discontinuity does not exist because all nodes are single valued. You can therefore expect to see the same plot within the solid. but the temperature profile between the interface and the first node in the fluid interpolates between the solid-side interface value and the first fluid node value. the 1:1 interface is single valued and takes the solid-side conservative value. In this case. duplicate nodes exist. but an ‘average' over the control volume adjacent to the boundary. . If you create a plot across the solid-fluid interface using conservative values of temperature. Short Variable Name: The name that must be used in CEL expressions. 166 Contains proprietary and confidential information of ANSYS. the conservative velocity calculated at the wall node is not zero. At a wall boundary node the difference between conservative and hybrid values can be illustrated by considering the case of the mass flow rate through the wall-adjacent control volume. Hybrid Values on a GGI Interface At a GGI interface. Inc. This is because values are interpolated from the interface into the bulk of the solid domain using the value for the solid-side node at the interface. Note The entries in the Units columns are SI but could as easily be any other system of units. Hence. This results in a temperature discontinuity at the interface. Conservative Values on a GGI Interface At a GGI interface. Conservative values should be used for all quantitative calculations. then you will see a sharp change in temperature across the interface.1 . and its subsidiaries and affiliates. Solid-Fluid Interface Variable Values Conservative Values at 1:1 Interface At a solid-fluid 1:1 interface. As a result. As a result.© 2009 ANSYS. All rights reserved.Solid-Fluid Interface Variable Values highlighted around the boundary node marked 1). The conservative value for the fluid-side node is the variable values averaged over the half of the control volume that lies in the fluid. An empty entry [ ] indicates a dimensionless variable. The conservative value for the solid-side node is the variable values averaged over the half on the control volume that lies inside the solid. Hybrid Values at 1:1 Interface When creating plots using hybrid variable values (the default in CFD-Post). Units: The default units for the variable. Many variables are relevant only for specific physical models. The information given in this section includes: • • • Long Variable Name: The name that you see in the user interface. Consider the example of heat transfer from a hot solid to a cool fluid when advection dominates within the fluid. Hybrid values of temperature on a GGI interface are set equal to the surface temperature. a plot of conservative values of temperature will generally show a discontinuity across a GGI interface. there is no discontinuity in hybrid values of temperature across a GGI interface. These values are representative of the temperature within the half-control volumes around the vertices on the interface. The surface temperature is usually between the fluid-side and solid-side temperatures. If a zero velocity was enforced at the boundary node. • In the Availability column: Release 12. then this would produce zero mass flow through the control volume. the CFX Solver calculates a "surface temperature" based on a flux-conservation equation for the 'control surfaces' that lie between the fluid side and the solid side. while values are interpolated from the interface into the bulk of the fluid domain using the value for the fluid-side node at the interface. which is clearly not correct. Inc. List of Field Variables This section contains a list of field variables that you may have defined in CFX-Pre or that are available for viewing in CFD-Post and exporting to other files. The fluid-side and solid-side temperatures are generally not equal. the CFX Solver calculates both fluid-side and solid-side temperatures based on heat flux conservation. For an explanation of the column headings. This number is useful when using the CFX Export facility. R. Information on obtaining details on all variables is available in the RULES and VARIABLES Files in the ANSYS CFX documentation. Note Variables with names shown in bold text are not output to CFD-Post.Common Variables Relevant for Most CFD Calculations • A number represents the user level (1 indicates that the variable appears in default lists. M. is a measure of the resistance of a fluid to shearing forces. For details. C. P. Common Variables Relevant for Most CFD Calculations The following table contains a list of variables (with both long and short variable names) that can be used when working with CFD calculations.1 . • Boundary (B): A B in this column indicates that the variable contains only non-zero values on the boundary of the model. Boundary-Value-Only Variables (p. and appears in the momentum equations. 38) for more details. See Boundary-Value-Only Variables (p. • • • • • • • • • • A indicates the variable is available for mesh adaption C indicates the variable is available in CEL DT indicates the variable is available for data transfer to ANSYS M indicates the variable is available for monitoring P indicates the variable is available for particle user-routine argument lists PR indicates the variable is available for particle results R indicates the variable is available to be output to the results. see List of Field Variables (p. In these cases. and its subsidiaries and affiliates. This is not a complete list of variables. Long Variable Name Density Short Variable Name density Units Availability Definition [kg m^-3] 1 A. Contains proprietary and confidential information of ANSYS. P. Velocitya vel [m s^-1] 1 Release 12. However.© 2009 ANSYS. Inc. see File Export Utility in the ANSYS CFX documentation. Using an expression to set the dynamic viscosity is possible. M. C. TS For Fixed and Variable Composition Mixture. For details. some of these variables can be output to CFD-Post by selecting them from the Extra Output Variables List on the Results tab of the Solver > Output Control details view of CFX-Pre. transient results. the density is determined by a mass fraction weighted harmonic average: YA YB + + ρA ρ B …+ YN ρN = 1 ρ mix Dynamic Viscosity viscosity [kg m^-1 s^-1] 2 A. 2 and 3 indicate that the variable appears in extended lists that you see when you click ). and backup files RA indicates the variable is available for radiation results TS indicates the variable is available for transient statistics Definition: Defines the variable. All rights reserved. the User Level may be different from that shown in the tables that follow. 38) in the ANSYS CFD-Post User's Guide describes the useful things that you can do with variables that are defined only on the boundaries of the model. also called absolute viscosity. see Non-Newtonian Flow in the CFX documentation. 167 . Velocity vector. R. Inc. Note that the CFX-Solver may sometimes override the user-level setting depending on the physics of the problem. TS Dynamic viscosity ( μ). 166). M. see Discretization C. of the Governing Equations in the ANSYS CFX documentation. Pressure is the total normal stress. For details. R. ideal gas equation of state and a general equation of state (CEL expression or RGP table). p tot. . P. M. P. TS Velocity u Velocity v Velocity w Pressure u v w p [m s^-1] 1 A.1 . C. R. R. X coordinate Y coordinate y [m] 2 C Z coordinate z [m] 2 C Kinematic Diffusivity visckin 2 C. Additionally. M. 168 Contains proprietary and confidential information of ANSYS. Static Pressure is the thermodynamic pressure. R. which means that when using the k-e turbulence model. For details. DT. and Components of velocity. P. P. TS [kg m^-1 s^-2] 1 A. TS Wall Shear Volume of Finite Volume wall shear Pa 3. Release 12. All rights reserved. and its subsidiaries and affiliates. is defined as the pressure that would exist at a point if the fluid was brought instantaneously to rest such that the dynamic energy of the flow converted to pressure without losses. M. C. TS Kinematic diffusivity describes how rapidly a scalar quantity would move through the fluid in the absence of convection. The following three sections describe how total pressure is computed for a pure component material with constant density. see Scalable Wall Functions in the ANSYS CFX documentation. Total Pressure ptot [kg m^-1 s^-2] 2 A. C. Inc.Common Variables Relevant for Most CFD Calculations Long Variable Name Short Variable Name Units Availability Definition A. R. see Scalable Wall Functions in the ANSYS CFX documentation. For details.© 2009 ANSYS. Inc. the kinematic diffusivity can have little effect because convection processes dominate over diffusion processes. in most cases this is the same as Pressure. C. M. The total pressure. P. TS Both Pressure and Total Pressure are measured relative to the reference pressure that you specified on the Domains panel in CFX-Pre. Pressure is the thermodynamic pressure plus the turbulent normal stress. R.B 3 Volume of finite volume. CFX solves for the relative Static Pressure (thermodynamic pressure) pstat in the flow field. TS x [m] 2 C Cartesian coordinate components. For convection-dominated flows. Static Pressure pstat [kg m^-1 s^-2] 3 is related to Absolute Pressure pabs = pstat + pref . M. Contains proprietary and confidential information of ANSYS. R. For details. R. this option is labeled Wall Heat Flux instead of Heat Flux. Release 12. 169 . R. C.1 . Variables Relevant for Turbulent Flows The following table contains a list of variables (with both long and short variable names) that can be used when working with turbulent flows. TS For details. unless specified as a Stn Frame variable. R. M. this option is labelled Heat Flux. when the bulk heat flux into both TS phases is set. Specific Heat Cp Capacity at Constant Pressure Specific Heat Cv Capacity at Constant Volume Thermal Conductivity cond [m^2 s^-2 K^-1] 2 A. When set on a per fluid basis. positive value indicates heat flux into the domain. [m^2 s^-2 K^-1] [kg m s^-3 K^-1] Thermal conductivity. P. Tstat. depending on the heat transfer model you select. Inc. C. and its subsidiaries and affiliates. TS For details see Non-Newtonian Flow in the ANSYS CFX documentation. TS For details. Inc. R. P. TS 2 A. C. Static Enthalpy enthalpy [m^2 s^-2] 2 A. temperature. see Thermal Conductivity in the ANSYS CFX documentation. Temperature T [K] The static temperature. C. λ . except that total enthalpy is used in the property relationships. Wall Heat Transfer htc Coefficient Total Enthalpy htot [W m^-2 K^-1] [m^2 s^-2] h tot For details. R.Variables Relevant for Turbulent Flows Long Variable Name Short Variable Name Units Availability Definition Shear Strain Rate sstrnr [s^-1] 2 A. see Static Enthalpy in the ANSYS CFX documentation. see Specific Heat Capacity in the ANSYS CFX documentation. M. the flow solver calculates either total or static TS enthalpy (corresponding to the total or thermal energy equations). TS The total temperature is derived from the concept of total enthalpy and is computed exactly the same way as static temperature. M. see List of Field Variables (p. is the property of a fluid that characterizes its ability to transfer heat by conduction. TS A. see Transport Equations in the ANSYS CFX documentation. P. C. is the thermodynamic A. a When a rotating frame of reference is used. DT. For an explanation of the column headings.© 2009 ANSYS. 2. 166). R. all variables in the CFX-5 results file are relative to the rotating frame. TS 2 A. For multiphase cases. Total Temperature Ttot [K] Wall Heat Flux Qwall [W m^-2] 2. In CFX. C. P. A C. M. C. see Wall Heat Transfer in the ANSYS CFX documentation. fluid. C. M. R.B A heat flux is specified across the wall boundary. M. DT. All rights reserved. and depends on the internal energy of the M. 1 1 A. R. TS For details. R.B C. R. TS assumed to be proportional to mean velocity gradients. TS the DES model 1 For details. P. TS [m^2 s^-2] Turbulence Eddy ed Dissipation [m^2 s^-3] Turbulent Eddy Frequency tef [s^-1] Eddy Viscosity eddy viscosity [kg m^-1 2 The “eddy viscosity model” proposes that turbulence s-1] A. see Statistical Reynolds Stresses in the ANSYS CFX documentation. Reynolds Stress components are automatically generated using running statistics of the instantaneous. R 3 M.1 . R 3 M.Variables Relevant for Turbulent Flows A B in the Type column indicates that the variable contains only non-zero values on the boundary of the model. C. For details. R 3 M. see Statistical Reynolds Stresses in the ANSYS CFX documentation. R 3 M. TS 1 The rate at which the velocity fluctuations dissipate. P. [m^2 s^-2] 2 This is a tensor quantity with six components. M. . For details. Inc. TS 1 A. All rights reserved. C. details. M. C. Long Variable Name Short Variable Name Units Availability Definition Blending desbf Function for DES model Turbulence Kinetic Energy ke [] 2 Controls blending between RANS and LES regimes for C. C. C. TS 3 M. M. R. transient velocity field. and in which the Reynolds stresses are R. P. In LES runs. R 3 C. see Statistical Reynolds Stresses and Reynolds Stress Turbulence Models in the ANSYS CFX documentation. R. Reynolds Stress rs Statistical rsstat uu Reynolds Stress uu Statistical rsstat vv Reynolds Stress vv Statistical rsstat ww Reynolds Stress ww Statistical rsstat uv Reynolds Stress uv Statistical rsstat uw Reynolds Stress uw Statistical rsstat vw Reynolds Stress vw Velocity Correlation uu uu [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] Release 12. A. see The k-epsilon Model in CFX in the ANSYS CFX documentation. P. M. Inc. M. R. R For details. R. A. 170 Contains proprietary and confidential information of ANSYS. consists of small eddies that are continuously forming and dissipating. M. For A. M. R 3 M. and its subsidiaries and affiliates. P. see Eddy Viscosity Turbulence Models in the ANSYS CFX documentation. For details.© 2009 ANSYS. see The k-epsilon Model in CFX in the ANSYS CFX documentation. Contains proprietary and confidential information of ANSYS. M. M. see Solver Yplus and Yplus in the ANSYS CFX documentation. Long Variable Name Thermal Expansivity Short Variable Name beta Units Availability Definition [K^ -1] 2 C For details. R.B C.Variables Relevant for Buoyant Flow Long Variable Name Velocity Correlation vv Velocity Correlation ww Velocity Correlation uv Velocity Correlation uw Velocity Correlation vw Yplus Short Variable Name vv Units Availability Definition [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [m^2 s^-2] [] 3 C.© 2009 ANSYS. TS Variables Relevant for Buoyant Flow The following table contains a list of variables (with both long and short variable names) that can be used when working with buoyant flows. see Solver Yplus and Yplus in the ANSYS CFX documentation. For an explanation of the column headings. TS A variable based on the distance from the wall to the first node and the wall shear stress. and its subsidiaries and affiliates. M. R. A deprecated internal variable.1 . M. R 3 C. R Defines the rate of change of the system volume with pressure. R 3 C. R − 1 ∂ρ ρ ∂T p Isothermal compisoT Compressibility [ms^2kg^-1] 2 C. R 3 C. Inc. Inc.B C. Variables Relevant for Compressible Flow The following table contains a list of variables (with both long and short variable names) that can be used when working with compressible flows. Long Variable Name Short Variable Name Units Availability Definition Isobaric compisoP Compressibility [K^-1] 2 C. M. 171 . 1 ∂ρ ρ ∂p T Release 12. 166). ww uv uw vw yplusstd Solver Yplus yplus [] 2. All rights reserved. R 2. For details. M. see Basic Capabilities Modeling > Physical Models > Buoyancy in the ANSYS CFX Solver Modeling Guide. see List of Field Variables (p. R 3 C. For details. M. DT. All rights reserved. TS Urel = Ustn − ω × R Total Temperature in Stn Frame Ttotstn [K] 2 A. The extent to which a material reduces its volume when it is subjected to compressive stresses at a constant value of entropy. Long Variable Name Short Variable Name Units Availability Definition Total Pressure in ptotstn Stn Frame [kg m^-1 s^-2] 2 The velocity in the rotating frame of reference is A. Inc. M. Variables Relevant for Calculations with a Rotating Frame of Reference The following table contains a list of variables (with both long and short variable names) that can be used when working with a rotating frame of reference. see List of Field Variables (p. C. TS and a value of 1 in the vicinity of a shock. P. Inc. P. For an explanation of the column headings. where ω is the angular velocity.Variables Relevant for Particle Tracking Long Variable Name Mach Number Short Variable Name Mach Units Availability Definition [] 1 For details. C. and Ustn is velocity in the stationary frame of reference. C. M User-specified latent heat for phase pairs involving a particle phase. defined as: R. Momentum source from particle phase to continuous phase. C. Shock Indicator shock indicator [] Isentropic compisoS Compressibility [ms^2kg^-1] 2 C. R. R. 172 Contains proprietary and confidential information of ANSYS. M. M. 166). TS vector. R. M. M. R ⎛ 1⎞ ⎛ ∂ ρ⎞ ⎜ ρ⎟ ⎜ ∂ p⎟ ⎝ ⎠ ⎝ ⎠s Variables Relevant for Particle Tracking The following table contains a list of variables (with both long and short variable names) that can be used when working with compressible flows. R Diameter of a particle phase. see List of Symbols in the CFX documentation. Particle Momentum Source ptmomsrc [] 2 A. A. C. Release 12. R Particle Diameter particle diameter [] 3 A. . R is the local radius M. and its subsidiaries and affiliates. M.1 . C. Long Variable Name Latent Heat Short Variable Name lheat Units User Level Definition [] 2 C. P.© 2009 ANSYS. R. TS 2 The variable takes a value of 0 away from a shock A. TS Variables Relevant for Parallel Calculations The following table contains a list of variables (with both long and short variable names) that can be used when working with parallel calculations. 173 . Mass Concentration mconc [kg m^-3] 2 A. For an explanation of the column headings. C. C. see List of Field Variables (p. 166). TS Mach Number in Machstn Stn Frame [] Velocity in Stn Frame velstn [m s^-1] 1 A. R. M. Long Variable Name Real Partition Number Short Variable Name Units Availability Definition [] 2 C. R. by mass. P. TS Variables Relevant for Multiphase Calculations The following table contains a list of variables (with both long and short variable names) that can be used when working with multiphase calculations. R.© 2009 ANSYS. and its subsidiaries and affiliates. Inc. Contains proprietary and confidential information of ANSYS. M. 166). R. M. see List of Field Variables (p. R The partition that the node was in for the parallel run. Long Variable Name Mass Fraction Short Variable Name mf Units Availability Definition [] 1 The fraction of a component in a multicomponent fluid A. C.Variables Relevant for Parallel Calculations Long Variable Name Short Variable Name Units Availability Definition Total Enthalpy in htotstn Stn Frame [kg m^2 s^-2] 2 For details. see List of Field Variables (p. Release 12.1 . TS 1 A. For an explanation of the column headings. TS The concentration of a component. see Rotating Frame Quantities in the A. M. 166). Inc. All rights reserved. M. M. For an explanation of the column headings. R. Variables Relevant for Multicomponent Calculations The following table contains a list of variables (with both long and short variable names) that can be used when working with multicomponent calculations. C. CFX documentation. C. P. For details. R. TS Variables Relevant for Radiation Calculations The following table contains a list of variables (with both long and short variable names) that can be used when working with radiation calculations. M. R. see Volume Fraction in the ANSYS CFX documentation. TS 2 Velocity of an algebraic slip component relative to the C. and the Wall Convective Heat Flux. TS Conservative vfc Volume Fraction [] 2 For details. R.Variables Relevant for Radiation Calculations Long Variable Name Interfacial Area Density Short Variable Name area density Units Availability Definition [m^-1] 3 C Interface area per unit volume for Eulerian multiphase fluid pairs. M. TS mixture. Fluid.B Release 12. DT.Velocity. and its subsidiaries and affiliates. R.B Wall Radiative Heat Flux represents the net radiative DT. Drift Velocity drift velocity [] Slip Reynolds Number Slip Velocity slip Re [] slipvel [] 1 Velocity of an algebraic slip component relative to the C. C. Interface mass transfer rate for Eulerian multiphase fluid pairs. P. see Volume Fraction in the ANSYS CFX A. A B in the Type column indicates that the variable contains only non-zero values on the boundary of the model. M.1 . documentation. the sum should be zero. C. All rights reserved. Interphase Mass ipmt rate Transfer Rate Volume Fraction vf [] 3 C [] 1 A.Volume Fraction multiplied by the A. Surface Tension surface tension [N m^-1] 2 Coefficient coefficient C Unclipped unclipped area [m^-1] Interfacial Area density Density Superficial Velocity volflx 3 C Similar to area density. 166). .© 2009 ANSYS. TS continuous component. R. Inc. Wall Heat Flux is sum of the Wall Radiative Heat Flux C. R. but values are not clipped to be non-zero. 3 C Reynolds number for Eulerian multiphase fluid pairs. It is computed as the difference between the radiative emission and the incoming radiative flux (Wall Irradiation Flux). R. C. Surface tension coefficient between fluids in a fluid pair. TS energy flux leaving the boundary. see List of Field Variables (p. M. For an explanation of the column headings. TS Wall Heat Flux Qwall [W m^-2] 2. Inc. Long Variable Name Wall Radiative Heat Flux Short Variable Name Qrad Units Availability Definition [W m^-2] 2. 174 Contains proprietary and confidential information of ANSYS. [m s^-1] 1 The Fluid. M. For an adiabatic wall. Long Variable Name Short Variable Name Total Enthalpy htot Units Availability Definition [m^2 s^-2] A. M.Variables for Total Enthalpies. TS A. P. R. DT. M. and Pressures The following table lists the names of the various total enthalpies. C. R. Variables for Total Enthalpies.stn Ttot. M. 166). R. Inc. DT. see Transport Equations in the ANSYS CFX documentation. C.rel TS [kg m^-1 s^-2] A.stn Total Temperature in Ttotstn Stn Frame Total Pressure in Rel ptotrel Frame Total Pressure ptot [kg m^-1 s^-2] A. TS A. P. Release 12. P. and Pressures Long Variable Name Short Variable Name Units Availability Definition Wall Irradiation irrad Flux [W m^-2] 2. TS [K] [K] [K] A. 166). M. DT. M. P. R. Temperatures. 175 . see List of Field Variables (p. Ptot TS [kg m^-1 s^-2] A. R. Contains proprietary and confidential information of ANSYS.B Wall Irradiation Flux represents the incoming radiative C. For details. C. C. DT.1 . C. All rights reserved. Many variables and expressions have a long and a short form (for example. 215). P. For an explanation of the column headings. M. Temperatures. C. M. see CFX Expression Language (CEL) in CFD-Post (p. flux. Ptot.stn TS Total Pressure in Stn ptotstn Frame Variables and Predefined Expressions Available in CEL Expressions The following is a table of the more common variables and predefined expressions that are available for use with CEL when defining expressions. Pressure or p). For simulations using the multiband model. C. M. see List of Field Variables (p. open the Expressions workspace. For an explanation of the column headings. Rothalpy rothalpy [m^2 s^-2] A. temperatures. R. and pressures when visualizing results in CFD-Post or for use in CEL expressions. It is computed as the solid angle integral of the incoming Radiative Intensity over a hemisphere on the TS boundary. R. R. C. and its subsidiaries and affiliates. Inc.© 2009 ANSYS. Ptot. TS Total Enthalpy in Stn htotstn Frame Total Temperature in Ttotrel Rel Frame Total Temperature Ttot h tot. the Wall Irradiation Flux for each spectral band is also available for post-processing. To view a complete list. TS I [m^2 s^-2] A. M.rel Ttot Ttot. R. C. R. Additional Variables and expressions are available in CFD-Post. TS h tot For details. P. 1. 176 Contains proprietary and confidential information of ANSYS. Common CEL Single-Value Variables and Predefined Expressions Long Variable Name Accumulated Coupling Step Short Variable Units Name acplgstep [] Availability 2 C [] 2 C [] 2 C [] 2 C [] 2 C [] 2 C sstep [] 2 C Time Step Size dtstep [s] 2 C Time t [s] 2 C Definition These single-value variables enable access to timestep. and Iteration Number Variables (p. Inc. Accumulated aitern Iteration Number Accumulated Time Step atstep Current Iteration citern Number Current Stagger cstagger Iteration Current Time Step Sequence Step ctstep Note Variables with names shown in bold text in the tables that follow are not output to CFD-Post. and iteration number in CEL expressions. . timestep interval. and its subsidiaries and affiliates. However. Release 12.1 .© 2009 ANSYS. some of these variables can be output to CFD-Post by selecting them from the Extra Output Variables List on the Results tab of the Solver > Output Control details view in CFX-Pre.Variables and Predefined Expressions Available in CEL Expressions Table 15. 182). For details. Timestep Interval. see Timestep. They may be useful in setting parameters such as the Physical Timescale via CEL expressions. Inc. All rights reserved. C. P. R.© 2009 ANSYS. TS Mach Number in Stationary Frame Release 12. 177 . M. TS Contact Area Fraction [AV name] Thermal Expansivity Effective Density Density af [] 3 M [AV name] beta [K^-1] 2 C deneff [kg m^-3] 3 A. R. C. C. R. M. TS density [kg m^-3] 2 A. P. R. TS Mach Number in Machstn Stn Frame [] 1 A. R. M. C.1 . P. M. Common CEL Field Variables and Predefined Expressions Long Variable Name Axial Distance Short Variable Units Name aaxis [m] Availability 2 C Definition Axial spatial location measured along the locally-defined axis from the origin of the latter. C. M. Contains proprietary and confidential information of ANSYS. M. C. M. R. Absorption Coefficient Boundary Distance absorp [m^-1] 1 C. TS bnd distance [m] 2 A. TS Mach Number Mach [] 1 A. TS Eddy Viscosity eddy viscosity [kg m^-1 s^-1] 1 A. All rights reserved. M. TS Boundary Scale bnd scale [m^-2] 3 C. P.2. z and aaxis are identical. M. TS Additional Variable name Turbulence Eddy ed Dissipation [m^2 s^-3] 1 A. R. Inc. R. R. and its subsidiaries and affiliates. When the locally-defined axis happens to be the z-axis. R. C. Inc. M.Variables and Predefined Expressions Available in CEL Expressions Table 15. TS Emissivity emis [] 1 C Extinction Coefficient Turbulence Kinetic Energy extinct [m^-1] 1 C ke [m^2 s^-2] 1 A. C. M. TS mf [] 1 A.Variables and Predefined Expressions Available in CEL Expressions Long Variable Name Mass Concentration Short Variable Units Name mconc [m^-3 kg] Availability 2 A. Inc. M. TS [m] 3 C. TS [] 2 C. and its subsidiaries and affiliates. TS Mixture Model mixture length [m] Length Scale scale Mixture Fraction mixvar Variance Molar Concentration molconc [] 3 M 1 A. P [m] 3 C. Simulation time at which the mesh was last re-initialized (most often due to interpolation that occurs as part of remeshing) Mixture Fraction Mean Definition Mass concentration of a component Mass Fraction Mesh Expansion mesh exp fact Factor Mesh Initialisation Time meshinittime Mixture Fraction mixfrc Molar Fraction Orthogonality orthanglemin Angle Minimum Orthogonality Factor orthfact Release 12. M. M. R. TS [m^-3 mol] 2 A. C. R. TS Molar Mass mw [kg mol^-1] 3 C. M. R. R. 178 Contains proprietary and confidential information of ANSYS. TS A measure of the average mesh orthogonality angle A measure of the worst mesh orthogonality angle A non-dimensional measure of the average mesh orthogonality The displacement relative to the previous mesh Ratio of largest to smallest sector volumes for each control volume. P. M. C. R. M. Inc. . M.© 2009 ANSYS. TS Conservative mfc Mass Fraction Mean Particle Diameter Mesh Displacement mean particle diameter meshdisp [] 2 A. TS molf [] 2 A. P Orthogonality Angle orthangle [rad] 2 C. TS [rad] 2 C.1 . R. All rights reserved. R. C. R. R. C. C. TS [s] 2 C [] 1 A. R. P. C. P. R. C. M. M. M. R. P. TS 2 C. M. 182). R. All rights reserved. M. Radial spatial location measured normal to the locally-defined axis. Inc. Contains proprietary and confidential information of ANSYS. Refractive Index refrac [] 1 C. Inc. Radial spatial location. TS [m^2 s^-2] 3 M. see CEL Variable rNoDim (p. rsstat ww.1 . TS [kg m^-1 s^-2] 1 A. C. rs vv. R. rsstat vw [m^2 s^-2] 2 A. All relative pressure specifications in CFX are relative to the Reference Pressure.Normalized Std Deviation. rs vw rsstat uu. see Setting a Reference Pressure in the ANSYS CFX documentation. and its subsidiaries and affiliates. M. TS Non dimensional radius rNoDim [] 2 C Non-dimensional radius (only available when a rotating domain exists). r and raxis are identical. 181). Statistical Reynolds Stress rsstat vv. R. When the locally-defined axis happens to be the z-axis. DT.© 2009 ANSYS. rs ww. rs uv. 179 . TS Radiation Intensity radint [kg s^-3] 1 A. C. R. P. rsstat uw. TS Absolute Pressure Reference Pressure pabs [kg m^-1 s^-2] 2 A. R. TS pref [kg m^-1 s^-2] 2 C The Reference Pressure is the absolute pressure datum from which all other pressure values are taken. P. M. For details. TS Radiative Emission. 2 2 Definition A measure of the worst mesh orthogonality angle Orthogonality orthfactmin Factor Minimum Pressure p Distance from local z axis Radius r [m] 2 C raxis [m] 2 C Radiative Emission Incident Radiation rademis [kg s^-3] 1 RA radinc [kg s^-3] 1 C.Variables and Predefined Expressions Available in CEL Expressions Long Variable Name Short Variable Units Name Availability 2 C. For details. For details. R. M. rsstat uv. rs uw. see CEL Variables r and theta (p. R. R The six Statistical Reynolds Stress components Release 12. M. M. C. The six Reynolds Stress components Reynolds Stress rs uu. r = x + y . P. This is written to the results file for Monte Carlo simulations as Radiation Intensity. C. and z coordinate directions [m s^-1] Velocity in Stationary Frame in the x. see CEL Variables r and theta (p. Inc. M. C. P.1 . R. DT. and its subsidiaries and affiliates.0 in subdomain. 0. TS sootmf [] 1 A. Inc. 182). TS Velocity in the x. M. TS sootncl [m^-3] 1 A. M. 181). see CEL Variable "subdomain" and CEL Function "inside" (p. R. C. when the latter is defined by the Coordinate Axis option. taxis is measured from the x(/y/z)-axis. inside variable (1. positive direction as per right-hand rule. For details. M. R. M. Definition Specific Volume specvol inside() inside() @<Locations> @<Locations> Theta taxis Turbulence Eddy tef Frequency [s^-1] 1 A. For details. see CEL Variable "subdomain" and CEL Function "inside" (p. arctan(y/x). TS [m^3 kg^-1] 3 A. y.0 in subdomain. and A. R.0 elsewhere). For details. C. TS Local Speed of speedofsound Sound Subdomain subdomain [m s^-1] 2 C. TS z coordinate directions 1 Release 12. R. M. C. R. R. 182). . [rad] 2 C taxis is the angular spatial location measured around the locally-defined axis. 180 Contains proprietary and confidential information of ANSYS.0 elsewhere). TS Velocity u Velocity v Velocity w Velocity in Stn Frame u Velocity in Stn Frame v Velocity in Stn Frame w u v w velstn u velstn v velstn w [m s^-1] 1 A. R. P. 0. R.Variables and Predefined Expressions Available in CEL Expressions Long Variable Name Scattering Coefficient Soot Mass Fraction Soot Nuclei Specific Concentration Short Variable Units Name scatter [m^-1] Availability 1 C. M. TS [] 2 C Subdomain variable (1. C. When the locally defined axis is the z(/x/y)-axis. TS Angle around local z axis Total Mesh Displacement theta [rad] 2 C Angle. All rights reserved. y. M. M. The total displacement relative to the initial mesh meshdisptot [m] 1 C.© 2009 ANSYS. C. R. if carbon dioxide is a material used in the fluid air. In a single phase simulation the fluid prefix may be omitted. C. then some of the system variables that you might expect to see are: • • • air.1 .© 2009 ANSYS. R.viscosity . P. C. C.carbondioxide. CEL Variables r and theta r is defined as the normal distance from the third axis with respect to the reference coordinate frame. such as pressure.density . TS Wall Scale wall scale [m^2] 3 M. R. and its subsidiaries and affiliates. Inc. R. Inc. The rotational axis can either be defined in the results file or in CFD-Post through the Initialization panel in the Turbo workspace. TS Definition Volume Fraction vf [m^2 s^-1] Wall Distance System Variable Prefixes In order to distinguish system variables of the different components and fluids in your CFX model. for instance the velocity profile at the inlet to a pipe. prefixes are used.the mass fraction of carbon dioxide in air. theta is defined as the angular rotation about the third axis with respect to the reference coordinate frame. Contains proprietary and confidential information of ANSYS.Variables and Predefined Expressions Available in CEL Expressions Long Variable Name Short Variable Units Name [] Availability 1 A. Note theta is expressed in radians and will have values between − π and π . r and theta are particularly useful for describing radial distributions.the density of air air. M. 2 A. All rights reserved. P. 181 . For multiphase cases a fluid prefix indicates a specific fluid. P. C.Conservative A. TS wall distance [m] 2 A. M. Release 12. omitting the prefix indicates a bulk or fluid independent variable. M. M. For example. R. TS Conservative vfc Volume Fraction Kinematic Viscosity visckin [] 2 The variable <fluid>.mf . The variables Radius and theta are available only when the rotational axis has been defined.the viscosity of air air. TS Volume Fraction should not usually be used for post-processing. citern gives the current coefficient loop number within the current timestep. sstep is the 'global' sequence time step. In CFD-Post. but allows a specific 2D or 3D location to be given. and iteration number in CEL expressions. Timestep Interval. timestep interval. CEL Variable "subdomain" and CEL Function "inside" subdomain is essentially a step function variable. citern gives the outer iteration number of the current run. Thus. It is a ratio of radii. and its subsidiaries and affiliates. . and Iteration Number Variables These variables allow access to timestep. 182 Contains proprietary and confidential information of ANSYS. Inc. It works in all subdomains but cannot be applied to specific subdomains (for example. defined to be zero at the minimum radius and unity at the maximum radius. where n is the number of coefficient loops. rNoDim is only available for domains defined with a rotating frame of reference.1 . r and theta with Respect to the Reference Coordinate Frame CEL Variable rNoDim rNoDim is a dimensionless system variable that can be useful for rotating machinery applications.Variables and Predefined Expressions Available in CEL Expressions Figure 15. only aitern (or. Release 12. 273 [K] * inside()@Subdomain 1 has a value of 273 [K] at points in Subdomain 1 and 0 [K] elsewhere. This is useful for describing different initial values or fluid properties in different regions of the domain. the location can be any 2D or 3D named sub-region of the physical location on which the expression is evaluated. irrespective of whether it is a restarted run. which accumulates across a restarted run. The location can also be an immersed solid domain. 157) in the ANSYS CFD-Post User's Guide. aitern gives the accumulated outer iteration number. Steady-State Runs In steady-state runs. atstep and ctstep are used for the accumulated and current timestep numbers of the outer timestep loop. defined to be unity within a subdomain and zero elsewhere. Transient Runs In transient runs. Furthermore.© 2009 ANSYS. so that in general: rNoDim = R − R min R max − R min where R is the radius of any point in the domain from the axis of rotation. The outer iteration number begins at 1 for each run. equivalently ctstep) are of use.1. Inc. The inside CEL function can be used in a similar way to the subdomain variable. It is equivalent to the Step value in the Timestep Selector (p. For example. Timestep. citern will cycle between 1 and n for each timestep during a transient run. They may be useful in setting parameters such as the Physical Timescale via CEL expressions. All rights reserved. equivalently atstep) and citern (or. aitern is equivalent to citern for transient runs. an expression for temperature in a subdomain could be 373*subdomain [K]). The trigonometric functions all work in terms of an angle in radians and a dimensionless ratio. Expression Properties There are three properties of expressions: • • • An expression is a simple expression if the only operations are +. / and there are no functions used in the expression.*4 is not a constant integer expression. z). if t is time and L is a length then the result of L/t has the same dimensions as speed. cstagger and acplgstep are also available.operators are only valid between expressions with the same dimensions and result in an expression of those dimensions. Scalar Expressions A scalar expression is a real valued expression using predefined variables. Both files are located in <CFXROOT>/etc/ and can be viewed in any text editor. 183 . 2*(1/2) is not a constant integer expression. *. however. since ^ is not in the list (+. Both files are located in <CFXROOT>/etc/ and can be viewed in any text editor. and literal constants (for example. An expression is a constant expression if all the numbers in the expression are explicit (that is. for instance.but this is also a valid dimension setting). acplgstep gives the accumulated coupling step. y. -. acplgstep is equivalent to atstep. For example. *. However. Also 3. System Variables are logically unavailable. Available and Unavailable Variables CFX System Variables and user-defined expressions will be available or unavailable depending on the simulation you are performing and the expressions you want to create. In others. sin() and exp()). Release 12. XÎ. constant. Inc.0). Moreover 2^3 is not a simple. mathematical function. then that expression will also be unavailable. An expression's value is a real value and has specified dimensions (except where it is dimensionless . Expressions are evaluated at runtime and in single precision floating point arithmetic. This gives the multi-field timestep number or "coupling step" number for the run. integer expression. variables. If. is not an integer. but no other system variables. where I is an integer. and accumulates across a restarted run. The + and .© 2009 ANSYS. integer expression. For example. temperature (T) and location (x. the availability of a System Variable is not allowed for physical model reasons. user variables. or an existing CEL expression. Inc. and dependencies. Expression Names Your CEL expression name can be any name that does not conflict with the name of a CFX system variable. which will cycle between 1 and n for each coupling step of the run. time (t) is not available for steady-state simulations. For example (3+5)/2 is a simple. since 3. Scalar expressions can include the operators + .1 . For transient ANSYS Multi-field runs where the CFX timestep is the same as the multi-field timestep. since the result of 1/2 is 0. The RULES and VARIABLES files provide information on valid options. 1. that expression depends on a system variable that is unavailable for a particular context.Variables and Predefined Expressions Available in CEL Expressions ANSYS Multi-field Runs For ANSYS Multi-field runs.* / and ^ and several of the mathematical functions found in standard Fortran (for example. constant. density can be a function of pressure (p). and its subsidiaries and affiliates. The * and / operators combine the dimensions of their operands in the usual fashion. All rights reserved. results in an expression whose dimensions are those of X to the power I. Note that literal constants have to be of the same dimension. /). they do not depend on values from the solver). Contains proprietary and confidential information of ANSYS. -. In some circumstances. not an integer.5. cstagger gives the current stagger iteration. Information on how to find dependencies for all parameters is available in the RULES and VARIABLES files. The expression definition can depend on any system variable. An expression is an integer expression if all the numbers in the expression are integers and the result of each function or operation is an integer. • • • Particle Track Variables (p. See Boundary-Value-Only Variables (p.© 2009 ANSYS. the User Level may be different from that shown in the table below. some of these variables can be output to CFD-Post by selecting them from the Extra Output Variables List on the Results tab of the Solver > Output Control details view of CFX-Pre. 38) for more details. Particle Track Variables Particle track variables are particle variables that are defined directly on each track. and they also cannot be monitored during a simulation. 184 Contains proprietary and confidential information of ANSYS. Many variables are relevant only for specific physical models. additional track variables can be specified in the argument list for the user routine. Particle track variables can be exported from CFD-Post along the particle tracks. Note The entries in the Units columns are SI but could as easily be any other system of units. 189) Some variables are defined only on the boundaries of the model. Note Particle track variables are not available for use in CEL expressions and general User Fortran. Inc. which are not available in CFD-Post: Release 12. and its subsidiaries and affiliates. Direct access to the particle track variables outside of CFD-Post is only possible if the raw track file is kept after a particle run. When using these variables in CFD-Post. For information on obtaining details on all variables. there are a limited number of useful things that you can do with these. Inc. For details. Boundary) User Level: This number is useful when using the CFX Export facility. These variables are defined on the particle positions for which track information is written to the results file. In these cases. Particle track variables can only be used in two ways: to color particle tracks in CFD-Post. .1 . • Type (User Level. For details. Units: The default units for the variable. 184) Particle Field Variables (p. 186) Particle Boundary Vertex Variables (p. see Boundary-Value-Only Variables (p. For Particle User Fortran. This section does not cover the complete list of variables. Short Variable Name: The name that must be used in CEL expressions.Particle Variables Generated by the Solver Particle Variables Generated by the Solver This section describes the following types of particle variables that you may have defined in CFX-Pre or that are available for viewing in CFD-Post and exporting to other files. Note Variables with names shown in bold text are not output to CFD-Post. However. see File Export Utility in the ANSYS CFX documentation. see RULES and VARIABLES Files in the ANSYS CFX documentation. 38) in the ANSYS CFD-Post User's Guide. An empty entry [ ] indicates a dimensionless variable. Note that the CFX-Solver may sometimes override the user-level setting depending on the physics of the problem. and to be used as input to Particle User Fortran. All rights reserved. The following information is given for particle variables described in this section: • • • Long Variable Name: The name that you see in the user interface. Boundary (B): A B in this column indicates that the variable contains only non-zero values on the boundary of the model. Inc.Velocity [kg] Particle total mass 2 PR [m/s] Particle velocity 1 PR <Particle Type>. 185 .Particle Time pttime [s] Simulation time 2 PR <Particle Type>. Contains proprietary and confidential information of ANSYS.Particle Track Variables Long Variable Name Short Variable Name Units Description Availability <Particle Type>. Particle temperature 1 PR [s] <Particle Type>.Particle Traveling Distance <Particle Type>.Velocity w Long Variable Name Particle Eotvos Number u v w [m/s] Particle velocity components in x.Temperature T [K] <Particle Type>.Particle Time. For steady-state simulations PR only. and its subsidiaries and affiliates. y.Particle Number Rate mean particle [m] diameter particle number rate [s^-1] Particle diameter 3 PR Particle number rate 3 PR <Particle Type>.Velocity u <Particle Type>. Inc.Total Particle ptmasst Mass <Particle Type>.Velocity v <Particle Type>.1 .Mean Particle Diameter <Particle Type>. All rights reserved. and z-direction 1 PR Short Variable Name pteo Units [] Availability 2 PR Particle Morton Number ptmo [] 2 PR Particle Nusselt Number ptnu [] 2 PR Particle Ohnesorge Number pton [] 2 PR Particle Reynolds Number ptre [] 2 PR Particle Weber Number a Particle Slip Velocity ptwe [] 2 PR ptslipvel [m s^-1] 2 PR Release 12.Particle Traveling Time ptdist [m] Distance along the particle track measured 2 from the injection point PR Time measured from the time of injection 2 of the particle.© 2009 ANSYS. this time is identical to <Particle Type>. and so this operation will be slower than coloring with a track variable. and its subsidiaries and affiliates. 186 Contains proprietary and confidential information of ANSYS. particle field variables can be used in the same way as particle track variables as input to particle User Fortran and for coloring tracks. the following variables are written to the results file: Long Variable Name Particle Energy Source Short Variable Name ptenysrc Units [W m^-3] Availability 2 A. . they can be monitored during a simulation.Mass Fraction Units Description Fraction of mass of a particular particle component Particle Field Variables Particle field variables are particle variables that are defined at the vertices of the fluid calculation.Particle Weber Number Units [-] Description Particle Weber number along track We = ρfVslip2 where Dp σ ρf = fluid density Vslip = slip velocity D p = particle diameter σ = surface tension coefficient Multi-component Particle Variable Long Variable Name <Particle Type>. The following particle variables are available as field variables: Particle Sources into the Coupled Fluid Phase For fully-coupled particle simulations involving energy. R Release 12. This means that particle field variables are available for use in CEL expressions and User Fortran. the field variables have to be interpolated onto the tracks. and are available for general post-processing in CFD-Post.<Particle Component>. In contrast to track variables. All rights reserved. Inc. Inc. When used for coloring tracks. C.1 . M. P.© 2009 ANSYS.Droplet Breakup Variable Long Variable Name Particle Position Short Variable Name ptpos Units [m] Availability 2 PR Particle Impact Angle b particle impact angle [radian] 3 PR a b Note: Weber number is based on particle density and particle slip velocity. these variables can be used in the same way as “standard” Eulerian variables. Additionally. Droplet Breakup Variable Long Variable Name <Particle Type>. Note: The impact angle is measured from the wall. momentum and mass transfer to the fluid phase. M. except for the Averaged Volume Fraction.© 2009 ANSYS. Particle Radiation Variables Long Variable Name Particle Radiative Emission Short Variable Name Units ptremiss [W m^-3] Availability 2 A. which may help with convergence or grid independence. Inc. C. M. the following Additional Variables are available a: Particle Mass Source ptmassrc [kg s^-1 m^-3] 2 A.<Particle Component>. M. R Particle Mass Source Coefficient ptmassrcc [kg s^-1 m^-3] 2 A. 187 vfpt [] 1 . C. C. All rights reserved. P. R For multi-component mass transfer. P. R a [W m^-3 K^-1] 2 The variables for multi-component take the following form: <Particle Type>. C. C. P. Inc. M. C. P. R Particles can also interact with the radiation field and either emit or absorb radiation. and its subsidiaries and affiliates. R Particle Momentum Source Coefficient ptmomsrcc [kg m^-3 s^-1] 2 A. C. M. P. P. P. Contains proprietary and confidential information of ANSYS. particle vertex variables are not written to the results file. R Particle Absorption Coefficient ptabscoef [m^-1] 2 A. R Total Particle Mass Source Coefficient ptmassrcctot [kg s^-1 m^-3] 2 A.1 . PR. Particle Vertex Variables By default. M. P. The following particle variables are available: Long Variable Name Averaged Velocity Short Variable Name Units averaged vel [m s^-1] Availability 1 A. R Particle Momentum Source ptmomsrc [kg m^-2 s^-2] 2 A. R Averaged Volume Fraction Release 12. C. R Total Particle Mass Source ptmassrctot [kg s^-1 m^-3] 2 A. M. M. For details. CEL expression or in (Particle) User Fortran.Particle Field Variables Long Variable Name Particle Energy Source Coefficient Short Variable Name ptenysrcc Units Availability A. C. A smoothing procedure can be applied to the particle source terms. see Particle Source Smoothing in the CFX documentation. M. The other vertex variables can be written to the results file if they are selected from the Extra Output Variables List in the Output Control section of CFX-Pre or if they are used in a monitor point. M. P.<Variable Name> Particle source terms are accumulated along the path of a particle through a control volume and stored at the corresponding vertex. C. P. P. C. P. R Averaged Mean Particle Diameter (D43) averaged mean particle [m] diameter 2 A. M. PR. . PR. R 2 A. C. M. M. P. the following additional vertex variables are available: Averaged Volume Fraction Wall vfptw [] 1 A. M.<Variable Name> Release 12. and its subsidiaries and affiliates. C. P. R a This variable takes the following form: <Particle Type>. C. M. P. M. PR. PR. M. C. C. C. PR. R 2 A. M. PR. PR. PR. C. R 2 A. C. C. R [s^-1] 2 A.© 2009 ANSYS. P. PR. R 2 A. All rights reserved. R Averaged Particle Time averaged pttime [s] 2 A. P. R 2 A. PR. Inc. M. 188 Contains proprietary and confidential information of ANSYS. PR.<Particle Component>. M. C. M. R Averaged Mass Fraction a averaged mf [] 1 A.1 . P. P.Particle Field Variables Long Variable Name Short Variable Name Units Availability A. R Averaged Temperature averaged temperature [K] 1 A. R Averaged Arithmetic Mean Particle Diameter (D10) averaged arithmetic [m] mean particle diameter Averaged Surface Mean Particle Diameter (D20) averaged surface mean [m] particle diameter Averaged Volume Mean Particle Diameter (D30) averaged volume mean [m] particle diameter Averaged Sauter Mean Particle Diameter (D32) averaged sauter mean [m] particle diameter Averaged Mass Mean Particle Diameter (D43) averaged mass mean particle diameter [m] Averaged Particle Number Rate averaged particle number rate For simulations with the particle wall film model activated. R Averaged Film Temperature averaged film temperature [K] 1 A. P. P. C. C. Inc. P. M. P. PR. M. PR. see Vertex Variable Smoothing in the ANSYS CFX documentation.2) Averaged Mass Fraction • • cP . R Momentum Flow Density [kg m^-1 s^-2] 2 B. Particle Boundary Vertex Variables Particle-boundary vertex variables are particle variables that are defined on the vertices of domain boundaries. You cannot use these variables in CEL expressions or User Fortran. They are normalized with the face area of the corresponding boundary control volume. outlet. 15. R Energy Flow Density [kg s^-3] 2 B. 15.1 . To reduce possible problems a smoothing option is available. Inc. R Available at walls only: Release 12. Inc. openings and interfaces: Mass Flow Density [kg m^-2 s^-1] 2 B. P N P · ∑ ( Δt mP N P ) Φ P= With: • ( ) (Eq. P: Particle specific heat capacity TP: Particle temperature · ∑ Δt m c. vertex variables may show an unsmooth spatial distribution. Contains proprietary and confidential information of ANSYS.3) mc. P T P · ∑ Δt mP N P cP. P: Mass of species c in the particle Due to the discrete nature of particles.© 2009 ANSYS. All rights reserved. 15. Long Variable Name Available at inlet. 189 Units Availability .1) Σ : Sum over all particles and time steps in a control volume Δ t: Particle integration time step · N : Particle number rate P mP: Particle mass Φ: Particle quantity Slightly different averaging procedures apply to particle temperature and particle mass fractions: Averaged Particle Temperature · ∑ Δt mP N P cP. and you cannot monitor them during a simulation. You can use these variables to color boundaries and to compute average or integrated values of the corresponding particle quantities. For details.Particle Field Variables Variable Calculations Particle vertex variables are calculated using the following averaging procedure: Φ P= With: • • • • • · ∑ ( Δt mP N P ΦP ) · ∑ ( Δt mP N P ) (Eq. and its subsidiaries and affiliates. which may lead to robustness problems. P Φ P= With: ( ( ) ) (Eq. R RMS Temperature rms temperature [K] 1 A. M. C. PR. P.1 . R Particle RMS Variables For some applications. C. these variables are also defined at the vertices of the fluid calculation. PR. R Time Integrated Wall Mass Flow Density [kg m^-2] 2 B. particle RMS variables are not written to the results file. . unless. R RMS Mean Particle Diameter rms mean particle diameter rms particle number rate [m] 3 A. and are available for general post-processing in CFD-Post. usage in a CEL expression or in User Fortran) or if the stochastic particle collision model is used in a simulation. P. C. M. Particle RMS variables are available for use in CEL expressions and User Fortran.© 2009 ANSYS. but also their standard deviation in the form of particle RMS variables. R RMS Particle Number Rate Variable Calculations Particle RMS variables are calculated using the following procedure: Release 12. R Wall Mass Flow Density [kg m^-2 s^-1] 2 B. Inc. and its subsidiaries and affiliates. it may be necessary to not only provide the mean values of particle quantities. M. Inc. 190 Contains proprietary and confidential information of ANSYS.Particle Field Variables Long Variable Name Wall Stress Units [kg m^-1 s^-2] Availability 2 B. R Time Integrated Momentum Flow Density Time Integrated Energy Flow Density [kg m^-1 s^-1] [kg s^-2] 2 B. M. R [s^-1] 3 A. they can be monitored during a simulation. Similar to particle vertex variables. R Erosion Rate Density [kg m^-2 s^-1] 2 B. P. By default. particle RMS variables can be used in the same way as particle track variables as input to particle User Fortran and for coloring tracks. particularly useful for simulations that use the stochastic particle collision model: Long Variable Name RMS Velocity Short Variable Name Units rms velocity [m s^-1] Availability 1 A. C. they have been explicitly requested by the user (selected from the Extra Output Variables List in the Output Control section of CFX-Pre. PR. All rights reserved. P. Additionally. PR. R Time Integrated Erosion Rate Density [kg m^-2] 2 B. The following particle variables are available as field variables. R Available in transient runs: Time Integrated Mass Flow Density [kg m^-2] 2 B. R. C. R. C. 15. this variable is used for controlling mesh stiffness near boundaries for moving mesh problems. M. Miscellaneous Variables Variable names in bold are not output to CFD-Post. R.1 . transient results. In the Availability column: • A number represents the user level (1 indicates that the variable appears in default lists. and backup files TS indicates the variable is available for transient statistics Short Variable Name Units aspect ratio [] Availability 2 C. TS Autoignition autoignition [] 1 A. TS Similar to wall scale. Contains proprietary and confidential information of ANSYS. R. M. see Vertex Variable Smoothing in the CFX documentation. M. R. as available for particle vertex variables. is available for particle RMS variables. TS Boundary Scale bnd scale [] 3 C.Miscellaneous Variables Φ = Φ + Φ′′ Φ rms = Φ′′ 2 = With: • • • • • (Φ − Φ ) = Φ2 − Φ 2 2 (Eq. and its subsidiaries and affiliates. 191 . M. TS Release 12. C. M. TS burnt density [kg m^-3] 2 A. 2 and 3 indicate that the variable appears in extended lists that you see when you click • • • • • • • • A indicates the variable is available for mesh adaption C indicates the variable is available in CEL DT indicates the variable is available for data transfer to ANSYS M indicates the variable is available for monitoring P indicates the variable is available for particle user routine argument lists PR indicates the variable is available for particle results R indicates the variable is available to be output to the results. All rights reserved. Definition ) Long Variable Name Aspect Ratio Burnt Absolute Temperature Burnt Density burnt Tabs [K] 2 A. Inc.© 2009 ANSYS. Inc. For details.4) Φ: Instantaneous particle quantity Φ : Average particle quantity Φ′′: Fluctuating particle quantity Φ 2 : Average of square of particle quantity Φ : Square of average of particle quantity 2 A smoothing option. M. TS Electric Field elec 1 C. R. R. Combustion with flame surface density models. External magnetic induction field specified by the user. TS [] 3 C.© 2009 ANSYS. M. R. TS jcur 1 C. TS Electrical Conductivity conelec 3 C. TS Electric Potential epot 1 C. 192 Contains proprietary and confidential information of ANSYS. M.1 . R. TS spfsd 2 A. R. TS Dynamic Diffusivity diffdyn 2 C. TS External Magnetic Induction bmagext [] 1 M. TS Electromagnetic Force Density Equivalence Ratio bfemag 3 R equivratio [] 2 A. M. All rights reserved. C. M. M. C. R. Definition Negative absolute values clipped for cavitation Electrical Permittivity permelec First Blending sstbf1 Function for BSL and SST model Second Blending Function for SST model Flame Surface Density Specific Flame Surface Density Frequency sstbf2 . TS Conservative Size Fraction Courant Number sfc [] 2 A. M. R. Combustion with flame surface density models. R. M. M. C. M. TS 3 C. TS [] 3 C. R. Inc. C.Miscellaneous Variables Long Variable Name Clipped Pressure Short Variable Name Units pclip [Pa] Availability 1 M. R. and its subsidiaries and affiliates. TS Cumulative Size Fraction Current Density csf [] 2 A. M. TS freq 3 Release 12. R. R. P. R. TS courant [] 2 C. R. M. C. M. R. Inc. M. TS fsd [m^-1] 1 A. R. C. M. R. TS [s] 2 A.© 2009 ANSYS. Inc.1 . M. C. M. C. TS Granular Temperature Group I Index grantemp [m^2 s^-2] 1 A. Inc. C. R. and its subsidiaries and affiliates. R. TS Particle Integration Timestep Isentropic Compressibility Isentropic Compression Efficiency particle integration timestep compisoS [s] 3 P [m s^2 kg^-1] 2 C. All rights reserved. M. R. R icompeff [] 2 C.Miscellaneous Variables Long Variable Name Short Variable Name Units Availability C Fuel Tracer trfuel [] 1 A. M. TS Residual material model or exhaust gas recirculation (EGR) Definition Ignition Delay Time tigndelay ⎛ 1⎞ ⎛ ∂ ρ⎞ ⎜ ρ⎟ ⎜ ∂ p⎟ ⎝ ⎠ ⎝ ⎠s Release 12. Contains proprietary and confidential information of ANSYS. M. TS groupi [] 2 C Group J Index groupj [] 2 C Group I Diameter diami 2 C Group J Diameter diamj 2 C Group I Mass massi 2 C Group J Mass massj 2 C Group I Lower Mass Group J Lower Mass Group I Upper Mass Group J Upper Mass Ignition Delay Elapsed Fraction massi lower 2 C massj lower 2 C massi upper 2 C massj upper 2 C ignfrc [] 2 A. R. 193 . C. R. R. Definition Isentropic Expansion iexpeff Efficiency Isentropic Total Enthalpy Isentropic Static Enthalpy Isobaric Compressibility htotisen − 1 ∂ρ ρ ∂T p Isothermal Compressibility 1 ∂ρ ρ ∂p T LES Dynamic Model dynmc Coefficient Laminar Burning Velocity Lighthill Stress velburnlam Release 12. M. M. R. 194 Contains proprietary and confidential information of ANSYS. TS bmagext 1 C. M. P. R. R.© 2009 ANSYS. R compisoT [m s^2 kg^-1] 2 C. Inc. M. TS [m s^-1] 2 A. R. TS 2 C. Inc. TS Magnetic Vector Potential Magnetic Permeability External Magnetic Induction Mass Flux bpot 1 C. R. TS lighthill stress tensor 2 A. C. TS permmag 3 C. and its subsidiaries and affiliates. TS enthisen 2 C. TS Magnetic Field hmag 2 C. R. R. M. M. R. TS compisoP [K^-1] 2 C. R. M. M. R. M.Miscellaneous Variables Long Variable Name Short Variable Name Units [] Availability 2 C. TS mfflux 2 R Mesh Diffusivity diffmesh [m^2 s^-1] 2 C. . C. M. M. M. TS Magnetic Induction bmag 1 C. TS Normal Area normarea [] 2 C Total Force Density forcetden 3 DT Normal area vectors. M. R [] 1 A. All rights reserved.1 . and its subsidiaries and affiliates. Total Pressure in Rel ptotrel Frame Turbulent Burning Velocity Mesh Velocity velburnturb Molar Reaction Rate reacrate Nonclipped Density densitync [kg m^-3] 2 C Normal Vector normal [] 2 C Orthogonality Factor Minimum Orthogonality Factor orthfactmin [] 2 C. M. TS Release 12. M. Nonclipped density for cavitation source Definition Based on relative frame total enthalpy. R. TS meshvel 1 C.Miscellaneous Variables Long Variable Name Short Variable Name Units Availability 2 A. M. TS Nonclipped Absolute pabsnc Pressure 3 A. Contains proprietary and confidential information of ANSYS. R. M. R. R. TS Orthogonality Angle orthanglemin Minimum Orthogonality Angle orthangle Particle Laplace Number Particle Turbulent Stokes Number Polytropic Compression Efficiency ptla [] 2 P ptstt [] 2 P pcompeff [] 2 C.© 2009 ANSYS. M. M. R. TS orthfact [] 2 C. M. TS 2 C. This is written to the . R. TS 2 C. 195 . TS [m s^-1] 2 A. R. M. All rights reserved. R. C.1 . M. C.res file for all cases that have cavitation. TS Mixture Fraction Scalar Dissipation Rate mixsclds [s^-1] 3 A. Inc. R. TS Nonclipped absolute pressure for cavitation source. R. R. P. C. C. Inc. TS 2 C. R. TS Polytropic Expansion pexpeff Efficiency [] 2 C. M. C. TS Temperature Variance Tvar 1 A. R. TS Solid Pressure Gradient solid pressure gradient [ ] 3 C. M. R. TS restitution coefficient [ ] 3 C. C. C. M. M. R. M. TS wreacprogsrc 3 A. M. M. M. and its subsidiaries and affiliates. R. R.1 . Inc. R.Miscellaneous Variables Long Variable Name Polytropic Total Enthalpy Polytropic Static Enthalpy Reaction Progress Short Variable Name Units htotpoly Availability 2 C. R. C. R. R. M. M. For premixed or partially premixed combustion. R. R. M. R. P. R. C. R. TS rotvel 2 C. M. M. TS mfresid [] 1 A. Residual material model or exhaust gas recirculation (EGR) Residual material model or exhaust gas recirculation (EGR) Definition Solid Shear Viscosity solid shear viscosity . C. TS [kg m^-1 s^-1] 3 C. TS Solid Pressure solid pressure [Pa] 3 A. TS enthpoly 2 C. C. TS Solid Bulk Viscosity solid bulk viscosity [kg m^-1 s^-1] 3 C. Inc. R. R. R. TS Static Entropy entropy 3 A.© 2009 ANSYS. M. TS Shear Velocity ustar 2 C Size Fraction sf [] 1 A. M. C. TS Weighted Reaction Progress Weighted Reaction Progress Source Residual Products Mass Fraction Residual Products Molar Fraction Restitution Coefficient Rotation Velocity wreacprog [] 2 A. TS Release 12. For premixed or partially premixed combustion. For premixed or partially premixed combustion. All rights reserved. TS reacprog [] 1 A. C. 196 Contains proprietary and confidential information of ANSYS. TS Rotational Energy rotenergy 2 C. TS molfresid [] 2 A. R. R. TS [K] 2 C. TS unburnt density [kg m^-3] 2 A. TS vorticity 2 A. Contains proprietary and confidential information of ANSYS. M. R. R. and its subsidiaries and affiliates. R. M. TS unburnt Cp [J kg^-1 K^-1] 2 A. M. C. R. R 3 DT Unburnt Absolute Temperature Unburnt Density unburnt Tabs [K] 2 A. R Total Density is the density evaluated at the Total Temperature and Total Pressure. TS Volume of Finite Volumes Vorticity volcvol 3 C. R. All rights reserved. M. 197 . M. C. R. R [kg m^-3] 2 A. TS dentot [kg m^-3] 2 A. C.1 . M. M. R. Vorticity in Stn Frame vortstn 2 A. TS Note that Vorticity is the same as Velocity. R. C. C. R. DT.© 2009 ANSYS. TS Wall External Heat htco Transfer Coefficient Wall Adjacent Temperature Wall Distance tnw wall distance [m] 2 A. Inc. M. TS volpor [] 2 C.Miscellaneous Variables Long Variable Name Time This Run Short Variable Name Units trun Availability 2 C Total Boundary Displacement Total Density bnddisptot 1 C. C.Curl. C. TS 2 R. P. TS Unburnt Thermal Conductivity Unburnt Specific Heat Capacity at Constant Pressure Volume Porosity unburnt cond [W m^-1 K^-1] 2 A. Inc. M. M. C. DT. Definition Total Density in Stn dentotstn Frame Total Density in Rel dentotrel Frame Total Force forcet [kg m^-3] 2 A. C. M. TS Release 12. C. M. TS Wall Normal Velocity Wall Scale nwallvel 2 C. TS QwallFlow 3 C. TS Definition User-specified external wall temperature for heat transfer coefficient boundary conditions.1 . C. R Wall Heat Transfer Coefficient Wall Heat Flow htc 2 C. TS 2 A.Miscellaneous Variables Long Variable Name Wall External Temperature Short Variable Name Units tnwo [K] Availability 2 DT. C. M. Inc. Inc. Wall Film Thickness film thickness [m] 2 C. R. TS vfs [] 2 A. R. C.© 2009 ANSYS. M. TS wall scale 3 R. M. DT. R. TS 1 C. M. . R. 198 Contains proprietary and confidential information of ANSYS. R. M. R. TS Tsuperheat 3 C Temperature above saturation Temperature below saturation Tsubcool 3 C Release 12. TS Wavelength in Vacuum Wavenumber in Vacuum wavelo 3 C waveno 3 C [m^-3] 2 C. and its subsidiaries and affiliates. M. R. TS Normalized Droplet spdropn Number Droplet Number spdrop Dynamic Bulk Viscosity Total MUSIG Volume Fraction Smoothed Volume Fraction Temperature Superheating Temperature Subcooling dynamic bulk viscosity vft [] 1 A. R. R. All rights reserved. 199 . The following restrictions apply to marked variables: 2d 2da 2dasw 3d bns bnv cpl cv des dil do dpm dtrm fwh e edc emm ewt gran h2o id ke kw les melt mix mp nox np nv p p1 available only for 2D flows available only for 2D axisymmetric flows (with or without swirl) available only for 2D axisymmetric swirl flows available only for 3D flows available only for broadband noise source models node values available at boundaries available only in the density-based solvers available only for cell values (Node Values option turned off) available only when the DES turbulence model is used not available with full multicomponent diffusion available only when the discrete ordinates radiation model is used available only for coupled discrete phase calculations available only when the discrete transfer radiation model is used available only with the Ffowcs Williams and Hawkings acoustics model available only for energy calculations available only with the EDC model for turbulence-chemistry interaction available also when the Eulerian multiphase model is used available only with the enhanced wall treatment available only if a granular phase is present available only when the mixture contains water available only when the ideal gas law is enabled for density available only when one of the k-epsilon turbulence models is used available only when one of the k-omega turbulence models is used available only when the LES turbulence model is used available only when the melting and solidification model is used available only when the multiphase mixture model is used available only for multiphase models available only for NOx calculations not available in parallel solvers uses explicit node value function available only in parallel solvers available only when the P-1 radiation model is used Release 12. which list the ANSYS FLUENT field variables and gives the equivalent ANSYS CFX variable. and its subsidiaries and affiliates. Inc. Translation is carried out according to the tables that follow. Inc. CFD-Post does not modify the variable names in the ANSYS FLUENT file. ANSYS FLUENT Field Variables Listed by Category By default. you need to convert variable names to CFX types. Contains proprietary and confidential information of ANSYS.© 2009 ANSYS. All rights reserved. where one exists. If you want to use all of the embedded CFD-Post macros and calculation options.1 . You can convert the variable names to CFX variable names by selecting the Translate variable names to CFX-Solver style names check box in the Edit > Options > Files menu.Chapter 16. 200 Contains proprietary and confidential information of ANSYS.1 . and its subsidiaries and affiliates. . ANSYS FLUENT Variable Static Pressure (bnv) Pressure Coefficient Dynamic Pressure Absolute Pressure (bnv) Total Pressure (bnv) Relative Total Pressure Density.© 2009 ANSYS..pdf pmx ppmx r rad rc rsm s2s sa seg sp sr sol soot stat stcm t turbo udm uds v available only for non-premixed combustion calculations available only for premixed combustion calculations available only for partially premixed combustion calculations available only when the Rosseland radiation model is used available only for radiation heat transfer calculations available only for finite-rate reactions available only when the Reynolds stress turbulence model is used available only when the surface-to-surface radiation model is used available only when the Spalart-Allmaras turbulence model is used available only in the pressure-based solver available only for species calculations available only for surface reactions available only when the solar model is used available only for soot calculations available only with data sampling for unsteady statistics available only for stiff chemistry calculations available only for turbulent flows available only when a turbomachinery topology has been defined available only when a user-defined memory is used available only when a user-defined scalar is used available only for viscous flows Table 16. Inc. Density Density All CFX Variable Pressure Pressure Coefficient Dynamic Pressure Absolute Pressure Total Pressure in Stn Frame Relative Total Pressure Density Density Release 12. Pressure and Density Categories Category Pressure.1. All rights reserved.... Inc. 201 . bnv) Swirl Velocity (2dasw... bnv) Relative Tangential Velocity Relative Mach Number (id) Grid X-Velocity (nv) Grid Y-Velocity (nv) Grid Z-Velocity (3d. Inc. Velocity Category Category Velocity. 3d) Z-Vorticity (v.2.© 2009 ANSYS. ANSYS FLUENT Variable Velocity Magnitude (bnv) X Velocity (bnv) Y Velocity (bnv) Z Velocity (3d. 3d) Cell Reynolds Number (v) Preconditioning Reference Velocity (cpl) CFX Variable Velocity in Stn Frame Velocity in Stn Frame u Velocity in Stn Frame v Velocity in Stn Frame w Velocity Circumferential Velocity Axial Velocity Radial Stream Function Velocity Circumferential Mach Number in Stn Frame Velocity Velocity u Velocity v Velocity w Velocity Axial Velocity Radial Velocity Circumferential Velocity Circumferential Mach Number Mesh Velocity X Mesh Velocity Y Mesh Velocity Z Velocity Angle Velocity Angle Vorticity in Stn Frame Vorticity in Stn Frame X Vorticity in Stn Frame Y Vorticity in Stn Frame Z Cell Reynolds Number Reference Velocity (Preconditioning) Release 12. and its subsidiaries and affiliates. bnv) Relative Axial Velocity (2da) Relative Radial Velocity (2da) Relative Swirl Velocity (2dasw. 3d) Y-Vorticity (v. Inc. bnv) Axial Velocity (2da or 3d) Radial Velocity Stream Function (2d) Tangential Velocity Mach Number (id) Relative Velocity Magnitude (bnv) Relative X Velocity (bnv) Relative Y Velocity (bnv) Relative Z Velocity (3d.Table 16. nv) Velocity Angle Relative Velocity Angle Vorticity Magnitude (v) X-Vorticity (v. Contains proprietary and confidential information of ANSYS.1 . All rights reserved. nv) Fine Scale Temperature (edc. 202 Contains proprietary and confidential information of ANSYS. nv) Enthalpy (e. p1. nv) Total Temperature (e.3. Absorption Coefficient (r.1 . do. 2dasw) Pull Velocity Circumferentiala a ANSYS CFD-Post naming convention Release 12. nv..© 2009 ANSYS. bnv.Incident Radiation Surface Cluster ID <component>. Temperature. v) Wall Temperature (Inner Surface) (e. Inc.Table 16. p1. 2da) Pull Velocity Radiala Swirl Pull Velocity (melt (if calculated). e) Wall Temperature (Outer Surface) (e. and Solidification/Melting Categories Category Temperature. or dtrm) Scattering Coefficient (r..Mass Fraction Contact Resistivity Pull Velocity Xa Pull Velocity Ya Pull Velocity Za Axial Pull Velocity (melt (if calculated). 2da) Pull Velocity Axiala Radial Pull Velocity (melt (if calculated).. . nv) Relative Total Temperature (e) Rothalpy (e. 3d) CFX Variable Temperature Total Temperature in Stn Frame Static Enthalpy Total Temperature Rothalpy Fine Scale Temperature Wall Temperature Outer Surface Wall Temperature Inner Surface Inner Wall Temperature Total Enthalpy in Stn Frame Total Enthalpy Deviation Static Entropy Total Energy in Stn Framea Internal Energy Absorption Coefficient Scattering Coefficient Refractive Index Radiation Temperature Incident Radiation <Band n>. Radiation. or do) Refractive Index (do) Radiation Temperature (p1 or do) Incident Radiation (p1 or do) Incident Radiation (Band n) (do (non-gray)) Surface Cluster ID (s2s) Solidification/Melting Liquid Fraction (melt) Contact Resistivity (melt) X Pull Velocity (melt (if calculated)) Y Pull Velocity (melt (if calculated)) Z Pull Velocity (melt (if calculated). All rights reserved. ANSYS FLUENT Variable Static Temperature (e. v) Inner Wall Temperature Total Enthalpy (e) Total Enthalpy Deviation (e) Entropy (e) Total Energy (e) Internal Energy (e) Radiation. Inc. and its subsidiaries and affiliates.. emm) Reynolds Stress uu Reynolds Stress vv Reynolds Stress ww Reynolds Stress uv Reynolds Stress uw Reynolds Stress vw Turbulence Intensity Turbulence Eddy Dissipation Turbulence Eddy Frequency Turbulence Kinetic Energy Productiona Eddy Viscosity (modified) Eddy Viscosity Effective Viscosity Turbulent Viscosity Ratio (ke. emm) Subgrid Kinetic Energy (les) Subgrid Turbulent Viscosity (les) Subgrid Effective Viscosity (les) Subgrid Turbulent Viscosity Ratio (les) Subgrid Filter Length (les) Effective Thermal Conductivity (t.Table 16.© 2009 ANSYS.. ke. 3d. kw. kw. or rsm) Turbulent Dissipation Rate (Epsilon) (ke or rsm. kw. kw. and its subsidiaries and affiliates. kw. or des) Effective Viscosity (sa. or rsm. rsm. emm) UV Reynolds Stress (rsm. or des. or rsm) Wall Yplus (t) Kinetic Energy (subgrid) Eddy Viscosity (subgrid) (unavailable) Eddy Viscosity Ratio (subgrid) (unavailable) Effective Thermal Conductivity Effective Prandtl Number Ystar Yplus Turbulent Reynolds Number (Re_y) (ke or rsm. Inc. e) Wall Ystar (ke. ANSYS FLUENT Variable CFX Variable Turbulent Kinetic Energy (k) (ke. sa. 203 . ke. or rsm.4. emm) WW Reynolds Stress (rsm. kw. kw. emm) Turbulence Intensity (ke. Turbulent Kinetic Energy bnv.. Contains proprietary and confidential information of ANSYS. rsm. Turbulent Reynolds Number ewt) Relative Length Scale (DES) (des) Relative Length Scale (DES) Release 12. or emm) UU Reynolds Stress (rsm. bnv. emm) VV Reynolds Stress (rsm. e) Effective Prandtl Number (t. or Eddy Viscosity Ratio des. emm) Modified Turbulent Viscosity (sa) Turbulent Viscosity (sa. Turbulence Category Category Turbulence. emm) UW Reynolds Stress (rsm. emm) VW Reynolds Stress (rsm. All rights reserved. 3d. rsm. nv. Inc. or emm) Specific Dissipation Rate (Omega) (kw) Production of k (ke.1 . nv. Surface Deposition Rate <Species-n>.Molar Arrhenius Reaction Ratea <Reaction-n>. Species. sp. or ppmx. nv) Fvar Prod (pdf or ppmx) Fvar2 Prod (pdf or ppmx) Scalar Dissipation (pdf or ppmx) Premixed Combustion.Thermal Diffusion Coefficient <Species-n>..Fine Scale Mass Fraction Fine Scale Transfer Rate 1-Fine Scale Volume Fraction <Reaction-n>. nv) Secondary Mean Mixture Fraction (pdf or ppmx.Table 16.Effective Diffusion Diffusivity a <Species-n>.1 .Surface Coveragea Relative Humidity Time Step Scale <Species-n>. pdf.Mole Fraction Molar Concentration of species-n (sp. and its subsidiaries and affiliates.Source Terma <Species-n>... cpl) Surface Deposition Rate of species-n (sr) Surface Coverage of species-n (sr) Relative Humidity (sp. h2o) Time Step Scale (sp. or ppmx. Progress Variable (pmx or ppmx. nv) Damkohler Number (pmx or ppmx) Stretch Factor (pmx or ppmx) Turbulent Flame Speed (pmx or ppmx) Static Temperature (pmx or ppmx) Product Formation Rate (pmx or ppmx) Laminar Flame Speed (pmx or ppmx) Critical Strain Rate (pmx or ppmx) Unburnt Fuel Mass Fraction (pmx or ppmx) Fvar Prod (unavailable) Scalar Dissipation Reaction Progress Damkohler Numbera Stretch Factora Turbulent Flame Speeda Temperature Product Formation Ratea Laminar Flame Speeda Critical Strain Ratea Unburnt Fuel Mass Fractiona Adiabatic Flame Temperature (pmx or ppmx) Adiabatic Flame Temperature a Release 12. Rate of Reaction-n (rc) Arrhenius Rate of Reaction-n (rc) Turbulent Rate of Reaction-n (rc.Molar Concentration ppmx) Lam Diff Coef of species-n (sp.. pdf. Pdf. Inc.Molar Turbulent Reaction Ratea Mean Fraction Secondary Mixture Fractiona Mixture Fraction Variance Secondary Mixture Fraction Variance (pdf or Secondary Mixture Fraction Variancea ppmx. All rights reserved. Reactions.. . nv) Mixture Fraction Variance (pdf or ppmx..© 2009 ANSYS. and Premixed Combustion Categories Category Species. t) Pdf. dil) Thermal Diff Coef of species-n (sp) Enthalpy of species-n (sp) species-n Source Term (rc. stcm) Fine Scale Mass fraction of species-n (edc) Fine Scale Transfer Rate (edc) 1-Fine Scale Volume Fraction (edc) Reactions.Laminar Diffusion Coefficient <Species-n>. pdf. Mean Mixture Fraction (pdf or ppmx. dil) Eff Diff Coef of species-n (t. ANSYS FLUENT Variable Mass fraction of species-n (sp..5. Inc. 204 Contains proprietary and confidential information of ANSYS.Molar Reaction Rate <Reaction-n>. nv) <Species-n>.Mass Fraction Mole fraction of species-n (sp. pdf. or <Species-n>. nv) CFX Variable <Species-n>.. or ppmx) <Species-n>.Static Enthalpy <Species-n>. Molar Reaction Ratea SNCR NO..1 .Molar Reaction Rate a Reburn NO.Density Soot Mass Sourcea Soot Nuclei Sourcea <variable>.Molar Reaction Rate Prompt NO..Density NH3.Molar Fraction HCN.Trnavg <variable>.Density HCN. Contains proprietary and confidential information of ANSYS.. and Unsteady Statistics Categories Category NOx.Mass Fraction N2O.Molar Reaction Ratea User NO. Mean quantity-n (stat) RMS quantity-n (stat) CFX Variable NO.Molar Fraction N2O.Table 16. Inc. Inc..© 2009 ANSYS.Density Temperature Variance Species Variancea Species 1 Variancea Species 2 Variancea NO Source a Thermal NO. NOx.Mass Fraction NO.Molar Reaction Rate a Soot Mass Fraction Soot Nuclei Specific Concentration Soot Molar Fractiona Soot. and its subsidiaries and affiliates.. ANSYS FLUENT Variable Mass fraction of NO (nox) Mass fraction of HCN (nox) Mass fraction of NH3 (nox) Mass fraction of N2O (nox) Mole fraction of NO (nox) Mole fraction of HCN (nox) Mole fraction of NH3 (nox) Mole fraction of N2O (nox) NO Density (nox) HCN Density (nox) NH3 Density (nox) N2O Density (nox) Variance of Temperature (nox) Variance of Species (nox) Variance of Species 1 (nox) Variance of Species 2 (nox) Rate of NO (nox) Rate of Thermal NO (nox) Rate of Prompt NO (nox) Rate of Fuel NO (nox) Rate of N2OPath NO (nox) Rate of Reburn NO (nox) Rate of SNCR NO (nox) Rate of USER NO (nox) Soot. Soot. All rights reserved..Mass Fraction NH3.Molar Fraction NO.Molar Fraction NH3. 205 .Mass Fraction HCN. Mass fraction of soot (soot) Mass fraction of Nuclei (soot) Mole fraction of soot (soot) Soot Density (soot) Rate of Soot (soot) Rate of Nuclei (soot) Unsteady Statistics.Density N2O.Molar Reaction Rate a N2OPath.6.Trnrms Release 12.Molar Reaction Ratea Fuel NO. rad) DPM Burnout (dpm.Particle Momentum Source Y <particle>. Granular Temperature (emm. and its subsidiaries and affiliates.Particle Momentum Source Z <particle>. e) CFX Variable <phase>. Particle Evaporation-Devolatilization e) DPM Concentration (dpm) DPM species-n Source (dpm. ANSYS FLUENT Variable Volume fraction (mp) DPM Mass Source (dpm) DPM Erosion (dpm.Volume Fraction <particle>.Particle Mass Source <particle>. sp. gran) <particle>. Phases. Inc..Particle Momentum Source X <particle>. Discrete Phase Model.7. e) DPM Absorption Coefficient (dpm. 2dasw) <particle>. cv) DPM X Momentum Source (dpm) DPM Y Momentum Source (dpm) DPM Z Momentum Source (dpm..1 . e) Granular Pressure.. sp.Granular Temperature Release 12.Table 16. gran) Granular Temperature.© 2009 ANSYS. 3d) DPM Sensible Enthalpy Source (dpm.Particle Absorption Coefficient <particle>.Particle Radiative Emission <particle>.Particle Wall Mass Flow Densitya <particle>.. cv) DPM Accretion (dpm. All rights reserved. rad) DPM Emission (dpm. .Particle Sensible Enthalpy Source <particle>. Granular Pressure (emm.Particle Swirl Momentum Source DPM Evaporation/Devolatilization (dpm. rad) DPM Scattering (dpm. 206 Contains proprietary and confidential information of ANSYS..Volume Fraction <Species-n>.Particle Radiative Scattering a Particle Burnout DPM Swirl Momentum Source (dpm. e) DPM Enthalpy Source (dpm.Granular Pressurea <phase>..Particle Energy Source <particle>.Particle Mass Source <phase>. Discrete Phase Model. Inc. sp... Granular Pressure. and Granular Temperature Categories Category Phases.Particle Erosion Rate Density a <particle>. of Scalar-n (uds) Surface Heat Transfer Coef. Properties. Heat Tran. v.Absorbed Radiation Flux Absorbed Visible Solar Flux Absorbed IR Solar Flux <Band-n>. pdf) Sound Speed (id) Wall Fluxes. Surface Nusselt Number Surface Stanton Number <Scalar-n> <Scalar-n>. cv) Skin Friction Coefficient (v. Inc. Wall Shear Stress (v. cv. cv. Surface Incident Radiation cv) Surface Heat Transfer Coef. cv. cv) User-Defined Scalars. Coef. cv) Transmitted Visible Solar Flux (sol. emm) Granular Conductivity (mix. gran) Thermal Conductivity (e.. dtrm. emm) Total Surface Heat Flux (e.Transmitted Radiation Flux Surface Incident Radiation (do.Diffusion Coefficient Release 12. cv) Radiation Heat Flux (rad. cv) Beam Irradiation Flux (Band-n) (do. cv) <Band-n>. v. ANSYS FLUENT Variable Molecular Viscosity (v) Diameter(mix.Granular Conductivity a Thermal Conductivity Specific Heat Capacity at Constant Pressure Specific Heat Ratioa R Gas Constant Prandtl Numbera Molar Massa Local Speed of Sound a Wall Shear Wall Shear X Wall Shear Y Wall Shear Z Wall Shear Axial Wall Shear Radial Wall Shear Circumferential Skin Friction Coefficient Wall Heat Flux Wall Radiative Heat Flux Solar Heat Flux <Band-n>.. emm) Z-Wall Shear Stress (v. v. cv) Reflected Radiation Flux (Band-n) (do. and User Defined Memory Categories Category Properties. 207 . cv) Transmitted IR Solar Flux (sol..8. Wall Func.. v) Specific Heat (Cp) (e) Specific Heat Ratio (gamma) (id) Gas Constant (R) (id) Molecular Prandtl Number (e.Beam Irradiation Flux Transmitted Radiation Flux (Band-n) (do. cv) Reflected IR Solar Flux (sol. emm) Axial-Wall Shear Stress (2da. emm) Y-Wall Shear Stress (v. cv) Radial-Wall Shear Stress (2da. v. Contains proprietary and confidential information of ANSYS.Table 16. cv) CFX Variable Dynamic Viscosity Mean Particle Diameter <phase>. emm) X-Wall Shear Stress (v. (e. Scalar-n (uds) Diffusion Coef. and its subsidiaries and affiliates. User Defined Scalars. cv) Swirl-Wall Shear Stress (2dasw. Coef. cv) Surface Nusselt Number (e. Wall Fluxes. v.Reflected Radiation Flux Reflected Visible Solar Flux Reflected IR Solar Flux Transmitted Visible Solar Flux Transmitted IR Solar Flux <Band-n>.. cv. cv. (e. All rights reserved. cv) Reflected Visible Solar Flux (sol. v) Mean Molecular Weight (seg. or s2s. Heat Tran. cv) Solar Heat Flux (sol. cv) Surface Stanton Number (e.1 . cv) Wall Func. 3d. cv) Absorbed Radiation Flux (Band-n) (do. Inc. cv) Absorbed IR Solar Flux (sol.© 2009 ANSYS. emm..cv) Absorbed Visible Solar Flux (sol. ANSYS FLUENT Variable User Memory n (udm) CFX Variable User Defined Memory <n> Table 16. Angular Coordinate (3d. Grid. and Adaption Categories Category Cell Info. Cell Info. nv) Axial Coordinate (nv) Angular Coordinate (3d. and its subsidiaries and affiliates. All rights reserved. nv) Abs..Category User-Defined Memory. ANSYS FLUENT Variable Cell Partition (np) Active Cell Partition (p) Stored Cell Partition (p) Cell Id (p) Cell Element Type Cell Zone Type Cell Zone Index Partition Neighbors Grid.. . Inc...© 2009 ANSYS.. Inc. 208 Contains proprietary and confidential information of ANSYS. X-Coordinate (nv) Y-Coordinate (nv) Z-Coordinate (3d.9. nv) Radial Coordinate (nv) X Surface Area Y Surface Area Z Surface Area (3d) X Face Area Y Face Area Z Face Area (3d) Cell Equiangle Skew Cell Equivolume Skew Cell Volume 2D Cell Volume (2da) Cell Wall Distance Face Handedness Face Squish Index Cell Squish Index Face Area X Face Area Y Face Area Z Cell Equiangle Skew Cell Equivolume Skew Cell Volume 2d Cell Volume Cell Wall Distance Face Handedness Face Squish Index Cell Squish Index CFX Variable Cell Partition Active Cell Partition Stored Cell Partition Cell Id Cell Element Type Cell Zone Type Cell Zone Index Partition Neighbors X Y Z Axial Coordinate Angular Coordinate Absolute Angular Coordinate Radial Angular Coordinate Release 12.1 .. turbo) Abs (H-C) Spanwise Coordinate (nv. Contains proprietary and confidential information of ANSYS. turbo) Adaption. turbo) Abs (C-H) Spanwise Coordinate (nv.© 2009 ANSYS.1 ..Table 16. turbo) Spanwise Coordinate (nv... Grid Category (Turbomachinery-Specific Variables) and Adaption Category Category Grid. All rights reserved. ANSYS FLUENT Variable Meridional Coordinate (nv. Adaption Function Adaption Curvature Adaption Space Gradient Adaption Iso-Value Existing Value Boundary Cell Distance Boundary Normal Distance Boundary Volume Distance (np) Cell Volume Change Cell Surface Area Cell Warpage Cell Children Cell Refine Level CFX Variable Meridional Coordinate Abs Meridional Coordinate Spanwise Coordinate Abs (H-C) Spanwise Coordinate Abs (C-H) Spanwise Coordinate Pitchwise Coordinate Abs Pitchwise Coordinate Adaption Function Adaption Curvature Adaption Space Gradient Adaption Iso-Value Existing Value Boundary Cell Distance Boundary Normal Distance Boundary Volume Distance Cell Volume Change Cell Surface Area Cell Warpage Cell Children Cell Refine Level Release 12. Inc. turbo) Abs Meridional Coordinate (nv. and its subsidiaries and affiliates.. turbo) Pitchwise Coordinate (nv.10. turbo) Abs Pitchwise Coordinate (nv. 209 . Inc. . and its subsidiaries and affiliates. e) Species-n Residual (cpl. 2dasw) Temperature Correction (cpl. 2da) Radial-Velocity Residual (cpl.© 2009 ANSYS. 2da) Swirl-Velocity Correction (cpl.Table 16. 3d) Axial-Velocity Correction (cpl. All rights reserved. 2dasw) Temperature Residual (cpl. 2da) Radial-Velocity Correction (cpl. e) Species-n Correction (cpl.. 3d) Axial-Velocity Residual (cpl. Residuals Category Category Residuals. Inc.Correction Release 12. 2da) Swirl-Velocity Residual (cpl. 210 Contains proprietary and confidential information of ANSYS. sp) CFX Variable Mass Imbalance Pressure Residual Residual u Velocity Residual v Velocity Residual w Velocity Residual Axial-Velocity Residual Radial-Velocity Residual Circumferential-Velocity Residual Temperature <Species-n>.Residual Time Step Pressure Correction u Velocity Correction v Velocity Correction w Velocity Correction Axial-Velocity Correction Radial-Velocity Correction Circumferential-Velocity Correction Temperature Correction <Species-n>. Inc.1 .. sp) Time Step (cpl) Pressure Correction (cpl) X-Velocity Correction (cpl) Y-Velocity Correction (cpl) Z-Velocity Correction (cpl. ANSYS FLUENT Variable Mass Imbalance (seg) Pressure Residual (cpl) X-Velocity Residual (cpl) Y-Velocity Residual (cpl) Z-Velocity Residual (cpl.11. sp) dX-Velocity/dz (3d) dY-Velocity/dz (3d) dZ-Velocity/dz (3d) d species-n/dz (cpl.© 2009 ANSYS. and its subsidiaries and affiliates. sp. Derivatives Category Category Derivatives. Contains proprietary and confidential information of ANSYS. sp) dX-Velocity/dy dY-Velocity/dy dZ-Velocity/dy (3d) dAxial-Velocity/dy (2da) dRadial-Velocity/dy (2da) dSwirl-Velocity/dy (2dasw) d species-n/dy (cpl.12.Table 16. 3d) dOmega/dx (2dasw) dOmega/dy (2dasw) dp-dX (seg) dp-dY (seg) dp-dZ (seg. 3d) CFX Variable Strain Rate du-Velocity-dx dv-Velocity-dx dw-Velocity-dx dAxial-Velocity-dx dRadial-Velocity-dx dCircumferential-Velocity-dx d<Species-n>-dx du-Velocity-dy dv-Velocity-dy dw-Velocity-dy dAxial-Velocity-dy dRadial-Velocity-dy dCircumferential-Velocity-dy d<Species-n>-dy du-Velocity-dz dv-Velocity-dz dw-Velocity-dz d<Species-n>-dz dOmega-dx dOmega-dy dp-dX dp-dY dp-dZ Release 12. Inc. 211 .. All rights reserved. Inc. ANSYS FLUENT Variable Strain Rate (v) dX-Velocity/dx dY-Velocity/dx dZ-Velocity/dx (3d) dAxial-Velocity/dx (2da) dRadial-Velocity/dx (2da) dSwirl-Velocity/dx (2dasw) d species-n/dx (cpl.1 .. When appropriate. as it appears in the Set Units panel. ANSYS FLUENT Variable Surface dpdt RMS (fwh) Acoustic Power Level (dB) (bns) Acoustic Power (bns) Jet Acoustic Power Level (dB) (bns. Acoustics Category Category Acoustics. Abs (H-C) Spanwise Coordinate (in the Grid... 2da) Jet Acoustic Power (bns. Absolute Pressure (in the Pressure.Alphabetical Listing of ANSYS FLUENT Field Variables and Their Definitions Table 16. and variables in the category are not listed individually.© 2009 ANSYS.. Its unit quantity is length. Inc. Inc. category) is the dimensional coordinate in the spanwise direction. Variables A-C Abs (C-H) Spanwise Coordinate (in the Grid. All rights reserved.13. category) is equal to the operating pressure plus the gauge pressure. the unit quantity is included.... . category) is the dimensional coordinate in the spanwise direction. Its unit quantity is angle. 3d) LEE Shear-Noise Z-Source (bns. Its unit quantity is pressure. 212 Contains proprietary and confidential information of ANSYS. category) is the dimensional coordinate in the circumferential (pitchwise) direction. 3d) LEE Total Noise Z-Source (bns. Its unit quantity is length. Abs Pitchwise Coordinate (in the Grid. See Operating Pressure in the ANSYS FLUENT documentation for details.. For some variables (such as residuals) a general definition is given under the category name. category) is the dimensional coordinate that follows the flow path from inlet to outlet. 2da) Surface Acoustic Power Level (dB) (bns) Surface Acoustic Power (bns) Lilley's Self-Noise Source (bns) Lilley's Shear-Noise Source (bns) Lilley's Total Noise Source (bns) LEE Self-Noise X-Source (bns) LEE Shear-Noise X-Source (bns) LEE Total Noise X-Source (bns) LEE Self-Noise Y-Source (bns) LEE Shear-Noise Y-Source (bns) LEE Total Noise Y-Source (bns) LEE Self-Noise Z-Source (bns. and its subsidiaries and affiliates. 3d) Lilley's Self-Noise Source Lilley's Shear-Noise Source Lilley's Total Noise Source LEE Self-Noise X-Source LEE Shear-Noise X-Source LEE Total Noise X-Source LEE Self-Noise Y-Source LEE Shear-Noise Y-Source LEE Total Noise Y-Source LEE Self-Noise Z-Source LEE Shear-Noise Z-Source LEE Total Noise Z-Source CFX Variable Surface dpdt RMS Acoustic Power Level (dB) Acoustic Power Jet Acoustic Power Level (dB) Jet Acoustic Power Alphabetical Listing of ANSYS FLUENT Field Variables and Their Definitions This section defines the ANSYS FLUENT field variables.. from casing to hub...1 . Release 12... from hub to casing. Its unit quantity is length. Abs Meridional Coordinate (in the Grid. The unit quantity for Absorption Coefficient is length-inverse. category) is the acoustic power per unit volume generated by isotropic turbulence It is available only when the Broadband Noise Sources acoustics model is being used.. Its unit quantity is power per volume.. Acoustic Power Level (dB) (in the Acoustics. you first select Static Pressure. Acoustic Power (in the Acoustics. Adaption Function (in the Adaption. category) is the amount of solar heat flux absorbed by a semi-transparent wall for a visible or infrared (IR) radiation. Adaption. category) is an integer identifier designating the partition to which a particular cell belongs. The active cell partition is used for the current calculation. Absorbed Visible Solar Flux. select Adaption Function. Absorption Coefficient (in the Radiation.. category) is the amount of radiative heat flux absorbed by a semi-transparent wall for a particular band of radiation. see Partitioning the Grid Manually in the ANSYS FLUENT documentation. Absorbed IR Solar Flux (in the Wall Fluxes. In problems in which the grid is divided into multiple partitions to be solved on multiple processors using the parallel version of ANSYS FLUENT.. For instance..© 2009 ANSYS. category) is the property of a medium that describes the amount of absorption of thermal radiation per unit path length within the medium. for example. category) is the desired field variable function.. Active Cell Partition (in the Cell Info.. includes field variables that are commonly used for adapting the grid. All rights reserved.1 ... It can be interpreted as the inverse of the mean free path that a photon will travel before being absorbed (if the absorption coefficient does not vary along the path). To display contours of the Laplacian of pressure. depending on the settings in the Gradient Adaption panel. Inc. category) can be either the Adaption Space Gradient or the Adaption Curvature.. Release 12.. category) is the first derivative of the desired field variable. the Adaption Curvature is the undivided Laplacian of the values in temporary cell storage. category) is the acoustic power per unit volume generated by isotropic turbulence and reported in dB It is available only when the Broadband Noise Sources acoustics model is being used.. while the stored cell partition (the last partition performed) is used when you save a case file. and finally click the Display button. Its unit quantity is heat-flux.. Inc. the partition ID can be used to determine the extent of the various groups of cells... See Partitioning the Grid Manually in the ANSYS FLUENT documentation for more information. Adaption Space Gradient (in the Adaption. For information about solution adaption. 213 . click the Compute (or Display) button.Variables A-C Absorbed Radiation Flux (Band-n) (in the Wall Fluxes. and its subsidiaries and affiliates.. Contains proprietary and confidential information of ANSYS.... Adaption Iso-Value (in the Adaption.. The angle is positive in the direction of cross-product between reference axis and radial vector. incompressible flows). and is the molecular weight of species in reaction . Axial Coordinate (in the Grid. where due to reaction . are the stoichiometric coefficients of species Angular Coordinate (in the Grid. For more information. this equation will either be scaled or normalized. category) is the distance from the origin in the axial direction.. see Gradient Adaption Approach in the ANSYS FLUENT documentation.© 2009 ANSYS... For more information. category) is given by: where represents the net effect of third bodies on the reaction rate. . Abs. Inc. this equation will either be scaled or normalized. Adaption Curvature (in the Adaption.. The axial direction for a 2D model is always Release 12. after the transformation.. viscous. Angular Coordinate (in the Grid. multiply the reported reaction . This assumes that.. 214 Contains proprietary and confidential information of ANSYS.. the default axial vector (z-axis) becomes the reference axis... Adiabatic Flame Temperature (in the Premixed Combustion.Variables A-C Depending on the settings in the Gradient Adaption panel. see Gradient Adaption Approach in the ANSYS FLUENT documentation.. This term is given by The reported value is independent of any particular species. The radial vector is obtained by transforming the default radial vector (y-axis) by the same rotation that was applied to the default axial vector (z-axis). Recommended for problems with shock waves (such as supersonic. All rights reserved.. To find the rate of production/destruction for a given species rate for reaction and by the term . The axis origin and (in 3D) direction is defined for each cell zone in the Fluid or Solid panel. Recommended for smooth solutions (that is.1 . category) is the angle between the radial vector and the position vector. Arrhenius Rate of Reaction-n (in the Reactions. category) is the adiabatic temperature of burnt products in a laminar premixed flame ( in Its unit quantity is temperature. Inc.. category) is the second derivative of the desired field variable. inviscid flows). and its subsidiaries and affiliates. Depending on the settings in the Gradient Adaption panel. category) is the absolute value of the Angular Coordinate defined above. category) is the axial-direction component of the pull velocity for the solid material in a continuous casting process.1 . category) is a nondimensional parameter calculated using the normalized angle deviation method. Axial Velocity (in the Velocity. Its unit quantity is velocity. All rights reserved. category) is the distance of the cell centroid from the closest boundary zone. Each cell can have one of the following element types: triangle 1 tetrahedron 2 quadrilateral 3 hexahedron 4 pyramid 5 wedge 6 Cell Equiangle Skew (in the Grid. and its subsidiaries and affiliates. Cell Equiangle Skew applies to all elements.... A value of 0 indicates a best case equiangular cell. Its unit quantity is pressure. category) is the cell volume distribution based on the Boundary Volume.. Axial-Wall Shear Stress (in the Wall Fluxes... this value corresponds to the selected phase in the Phase drop-down list. and is defined as where • • • is the largest angle in the face or cell is the smallest angle in the face or cell is the angle for an equiangular face or cell (for example. Axial Pull Velocity (in the Solidification/Melting.. category) is a binary identifier based on whether a cell is the product of a cell subdivision in the hanging-node adaption process (value = 1) or not (value = 0). and the axial direction for a 2D axisymmetric model is always the x direction.... Inc... Cell Children (in the Adaption..© 2009 ANSYS. Cell Element Type (in the Cell Info. and a value of 1 indicates a completely degenerate cell.. Release 12.. See Boundary Adaption in the ANSYS FLUENT documentation for details. 215 . and normal distance from the selected Boundary Zones defined in the Boundary Adaption panel. category) is an integer that indicates the approximate number of cells from a boundary zone. Growth Factor. category) is the component of velocity in the axial direction.. Boundary Cell Distance (in the Adaption. category) is the integer cell element type identification number. Its unit quantity is velocity.) For multiphase models. category) is the axial component of the force acting tangential to the surface due to friction. (See Velocity Reporting Options in the ANSYS FLUENT documentation for details.Variables A-C the z direction.. 60 for a triangle and 90 for a square). Boundary Volume Distance (in the Adaption. Boundary Normal Distance (in the Adaption. Beam Irradiation Flux (Band-b) (in the Wall Fluxes. Inc. category) is specified as an incident heat flux ( ) for each wavelength band.. Contains proprietary and confidential information of ANSYS.. Degenerate cells (slivers) are characterized by nodes that are nearly coplanar (collinear in 2D).. The unit quantity for Axial Coordinate is length. includes quantities that identify the cell and its relationship to other cells. For example. category) is a nondimensional parameter calculated using the volume deviation method. and is defined as where optimal-cell-size is the size of an equilateral cell with the same circumradius. Cell Equivolume Skew applies only to triangular and tetrahedral elements. category) is the value of the Reynolds number in a cell. category) is the total surface area of the cell.. Inc. . Cell Volume (in the Grid...1 .© 2009 ANSYS. In problems in which the grid is divided into multiple partitions to be solved on multiple processors using the parallel version of ANSYS FLUENT. Inc. 216 Contains proprietary and confidential information of ANSYS. compared with the original grid. All rights reserved. is the effective viscosity (laminar plus turbulent). category) is a unique integer identifier associated with each cell. In 2D the volume is the area of the cell multiplied by the unit depth. if one quad cell is split into four quads... and is computed by summing the area of the faces that compose the cell. If the resulting four quads are split again. Cell Id (in the Cell Info. A value of 0 indicates a best case equilateral cell and a value of 1 indicates a completely degenerate cell.. the cell volume is calculated using a reference depth of 1 radian. the Cell Refine Level for each of the four new quads will be 1. Degenerate cells (slivers) are characterized by nodes that are nearly coplanar (collinear in 2D). category) is an integer that indicates the number of times a cell has been subdivided in the hanging node adaption process. the Cell Refine Level for each of the resulting 16 quads will be 2. and is calculated from the dot products of each vector pointing from the centroid of a cell toward the center of each of its faces. Cell Reynolds Number (in the Velocity. Cell Refine Level (in the Adaption. Release 12. is velocity magnitude. the partition ID can be used to determine the extent of the various groups of cells. and the corresponding face area vector as Therefore. Cell Partition (in the Cell Info. category) is the volume of a cell. category) is a measure of the quality of a mesh.Variables A-C Cell Equivolume Skew (in the Grid.) Cell Reynolds Number is defined as where is density.. Cell Surface Area (in the Adaption. For axisymmetric cases. and its subsidiaries and affiliates. The unit quantity of Cell Volume is volume. the worst cells will have a Cell Squish Index close to 1. (Reynolds number is a dimensionless parameter that is the ratio of inertia forces to viscous forces...... and Cell Volume^1/2 for 2D cases and Cell Volume^1/3 in 3D or axisymmetric cases... Cell Info. is Cell Squish Index (in the Grid... category) is an integer identifier designating the partition to which a particular cell belongs... category) is the maximum volume ratio of the current cell and its neighbors. category) is the mass per unit volume of the fluid.. 217 . the 2D cell volume is scaled by the radius... where is the contact resistance. is the liquid fraction. and is the cell height of the wall-adjacent cell..1 .. Plots or reports of Density include only fluid cell zones. category) is a parameter that takes into account the stretching and extinction of premixed flames ( in Its unit quantity is time-inverse.. For multiphase models.. category) is the integer cell zone identification number. For an axisymmetric computation.. category) is the additional resistance at the wall due to contact resistance. Cell Volume Change (in the Adaption. category) is the square root of the ratio of the distance between the cell centroid and cell circumcenter and the circumcenter radius: Cell Zone Index (in the Cell Info. Cell Zone Type (in the Cell Info. includes variables related to density.. and an exterior cell (parallel solver) has a type ID of 21. and its subsidiaries and affiliates. Critical Strain Rate (in the Premixed Combustion. Its unit quantity is area.Variables D-I 2D Cell Volume (in the Grid. You can create a custom function using the Custom Field Function Calculator panel. this value corresponds to the selected phase in the Phase drop-down list.... category) is the integer cell zone type ID.© 2009 ANSYS. the cell zone ID can be used to identify the various groups of cells. Cell Warpage (in the Adaption. It is equal to .. The unit quantity for Contact Resistivity is thermal-resistivity.. Density. Release 12. Density (in the Density. Inc. Contains proprietary and confidential information of ANSYS. All rights reserved. The unit quantity for Density is density. A fluid cell has a type ID of 1.. Inc. Cell Wall Distance (in the Grid. category) is a nondimensional parameter that is defined as the ratio of turbulent to chemical time scales.... See Custom Field Functions in the ANSYS FLUENT documentation for details. Contact Resistivity (in the Solidification/Melting. category) is the two-dimensional volume of a cell in an axisymmetric computation. Variables D-I Damkohler Number (in the Premixed Combustion.. category) is the distribution of the normal distance of each cell centroid from the wall boundaries.. In problems that have more than one cell zone. are scalar field functions defined by you... Custom Field Functions. Its unit quantity is length... All defined custom field functions will be listed in the lower drop-down list. a solid cell has a type ID of 17. ..© 2009 ANSYS. category) is the accretion rate calculated at a wall boundary: where is the mass flow rate of the particle stream. This item will appear only if the optional erosion/accretion model is enabled. See Modeling Discrete Phase in the ANSYS FLUENT documentation for details about this model.... includes quantities related to the discrete phase model. See the separate UDF manual for details about defining user-defined scalars. Discrete Phase Model. category) is the mass per unit volume of the fluid or solid material. Diameter (in the Properties. DPM Burnout (in the Discrete Phase Model.Variables D-I Density All (in the Density. DPM Accretion (in the Discrete Phase Model.. All rights reserved. category) is the exchange of enthalpy (sensible enthalpy plus heat of formation) from the discrete phase to the continuous phase. Derivatives. You can compute first derivatives of velocity.. Release 12. . DPM Concentration (in the Discrete Phase Model. angular velocity.. of Scalar-n (in the User Defined Scalars. Its unit quantity is heat-generation-rate. and species in the density-based solvers.. Plots or reports of Density All include both fluid and solid cell zones.. and its subsidiaries and affiliates. Its unit quantity is length..1 . or bubbles of the secondary phase selected in the Phase drop-down list.. category) is the diameter of particles.. The unit quantity for DPM Accretion is mass-flux. The burnout exchange has units of mass-flow. which is in Its unit quantity is length-inverse. are the viscous derivatives. dX-Velocity/dx is the first derivative of the x component of velocity with respect to the x-coordinate direction. category) is the absorption coefficient for discrete-phase calculations that involve radiation. Diffusion Coef... The unit quantity for DPM Enthalpy Source is power. The exchange is positive when the particles are a source of heat in the continuous phase. For example. category) is the exchange of mass from the discrete to the continuous phase for the combustion law (Law 5) and is proportional to the solid phase reaction rate. Its unit quantity is density. DPM Enthalpy Source (in the Discrete Phase Model. category) is the diffusion coefficient for the nth user-defined scalar transport equation. DPM Emission (in the Discrete Phase Model. Inc. Inc. DPM Absorption Coefficient (in the Discrete Phase Model. droplets... and pressure in the pressure-based solver... category) is the total concentration of the discrete phase. The unit quantity for Density All is density.. and first derivatives of velocity. 218 Contains proprietary and confidential information of ANSYS. angular velocity. category) is the amount of radiation emitted by a discrete-phase particle per unit volume. temperature... and is the area of the wall face where the particle strikes the boundary. See Monitoring Erosion/Accretion of Particles at Walls in the ANSYS FLUENT documentation for details. is the function specified in the Wall panel. due to droplet-particle evaporation or combusting-particle devolatilization. the mass source for each individual species (DPM species-n Source.1 ... The unit quantity is force.. category) is the exchange of swirl momentum from the discrete phase to the continuous phase. below). due to droplet-particle evaporation or combusting-particle devolatilization. category) is the total exchange of mass from the discrete phase to the continuous phase. category) is the exchange of mass. Its unit quantity is power. The unit quantity for DPM Evaporation/Devolatilization is mass-flow. category) is the exchange of mass. The exchange is positive when the particles are a source of heat in the continuous phase. DPM Sensible Enthalpy Source (in the Discrete Phase Model. The unit quantity for DPM Mass Source is mass-flow. See Monitoring Erosion/Accretion of Particles at Walls in the ANSYS FLUENT documentation for details. from the discrete phase to the evaporating or devolatilizing species. category) is the erosion rate calculated at a wall boundary face: where is the mass flow rate of the particle stream. DPM Evaporation/Devolatilization (in the Discrete Phase Model. Release 12.. and its subsidiaries and affiliates. category) is the exchange of sensible enthalpy from the discrete phase to the continuous phase. is the impact angle of the particle path with the wall face..) These species are specified in the Set Injection Properties panel... (The name of the species will replace species-n in DPM species-n Source. This value is positive when the particles are a source of momentum in the continuous phase. DPM Mass Source (in the Discrete Phase Model. use DPM Evaporation/Devolatilization instead.. and is the area of the wall face where the particle strikes the boundary. All rights reserved.© 2009 ANSYS.Variables D-I DPM Erosion (in the Discrete Phase Model. DPM species-n Source (in the Discrete Phase Model. 219 . The mass exchange is positive when the particles are a source of mass in the continuous phase. This item will appear only if the optional erosion/accretion model is enabled.. Contains proprietary and confidential information of ANSYS. Inc. If you are not using the non-premixed combustion model. The unit quantity for DPM Erosion is mass-flux. Note that this variable will not be available if you are using the non-premixed combustion model. from the discrete phase to the evaporating or devolatilizing species. DPM Mass Source will be equal to the sum of all species mass sources (DPM species-n Source. Inc. The unit quantity is mass-flow.. DPM Scattering (in the Discrete Phase Model. below) is also available. category) is the scattering coefficient for discrete-phase calculations that involve radiation ( in Its unit quantity is length-inverse. as described in Defining Injection Properties. DPM Swirl Momentum Source (in the Discrete Phase Model.. only this sum is available. if you are using the non-premixed combustion model. it will be equal to DPM Burnout plus DPM Evaporation/Devolatilization. for non-premixed combustion.. If you are not using the non-premixed combustion model... For compressible flows.. Eff Diff Coef of species-n (in the Species. Its unit quantity is thermal-conductivity. These values are positive when the particles are a source of momentum in the continuous phase. category) are the exchange of x-.) The unit quantity is mass-diffusivity. below. category) is the sum of the laminar and turbulent diffusion coefficients of a species into the mixture: (The name of the species will replace species-n in Eff Diff Coef of species-n. Effective Prandtl Number (in the Turbulence. and its subsidiaries and affiliates. where and are. Its unit quantity is viscosity.1 . A large thermal conductivity is associated with a good heat conductor and a small thermal conductivity with a poor heat conductor (good insulator). Effective Thermal Conductivity (in the Properties. y-. Viscosity. the mass fraction and enthalpy of species ... and x-direction momentum from the discrete phase to the continuous phase.© 2009 ANSYS.... Inc.. . of the fluid. (See Enthalpy of species-n. category) is defined differently for compressible and incompressible flows.Variables D-I DPM X. Its unit quantity is pressure. Inc. All rights reserved. category) is the ratio specific heat.. where is the effective viscosity. is defined by the ratio of shear stress to the rate of shear. The unit quantity is force. Dynamic Pressure (in the Pressure. the second term on the right-hand side of Release 12. category) is defined as . Enthalpy (in the Temperature.. . and for incompressible flows. respectively. category) is the sum of the laminar and turbulent thermal conductivities. and depending on the solver and models in use. 220 Contains proprietary and confidential information of ANSYS. .... Z Momentum Source (in the Discrete Phase Model.) For the pressure-based solver. is the is the effective thermal conductivity.. Y. Effective Viscosity (in the Turbulence. category) is the sum of the laminar and turbulent viscosities of the fluid.. and . 1 . It can be used to locate mesh problems. 221 . The quantity: where is the formation enthalpy of species at the reference temperature only for non-diabatic PDF cases.. The unit quantity for Enthalpy is specific-energy. Contains proprietary and confidential information of ANSYS.© 2009 ANSYS. this value corresponds to the selected phase in the Phase drop-down list. category) is defined differently depending on the solver and models options in use.. The unit quantity for Enthalpy of species-n is Entropy (in the Temperature. is reported where specific-energy. temperature.. and zero elsewhere. The quantity: .. and is where is computed from .Variables D-I is included only if the pressure work term is included in the energy equation (see Inclusion of Pressure Work and Kinetic Energy Terms in the ANSYS FLUENT documentation. or if the density-based solver is selected. the entropy is computed using the equation where is the specific heat at constant pressure and unit quantity for entropy is specific-heat. For compressible flows. Inc. category) is a parameter that is equal to one in cells that are adjacent to left-handed faces. is defined in the Reference Values panel. Inc. For incompressible flow. the Enthalpy plots consist of the thermal (or sensible) plus chemical energy. For all species models. and the reference pressure and density are defined in the Reference Values panel. Enthalpy of species-n (in the Species. category) is a thermodynamic property defined by the equation where "rev" indicates an integration along a reversible path connecting two states. Release 12.. The Existing Value (in the Adaption. the last value that you displayed or computed). is reported in all other cases. Face Handedness (in the Grid. For multiphase models. entropy is computed using the equation is heat.. and its subsidiaries and affiliates.. All rights reserved. category) is the value that presently resides in the temporary space reserved for cell variables (that is.. 1 . category) is the temperature of the fine scales.. category) is a function of the fine scale volume fraction ( in where * denotes fine-scale quantities. and is calculated from the dot products of each face area vector. category) is a measure of the quality of a mesh. category) is the term in Fine Scale Temperature (in the Temperature. and its subsidiaries and affiliates. category) is the transfer rate of the fine scales. which is equal to the inverse of the time scale ( in Its unit quantity is time-inverse.1377). which is calculated from the enthalpy when the reaction proceeds over the time scale ( in which is governed by the Arrhenius rates of Its unit quantity is temperature..... Inc. All rights reserved. is the kinematic Release 12. The quantity is subtracted from unity to make it easier to interpret. .. and the vector that connects the centroids of the two adjacent cells as Therefore. Fine Scale Transfer Rate (in the Species..Variables D-I Face Squish Index (in the Grid.. 1-Fine Scale Volume Fraction (in the Species. Fine Scale Mass Fraction of species-n (in the Species. 222 Contains proprietary and confidential information of ANSYS. the worst cells will have a Face Squish Index close to 1. Inc. and viscosity.. is the volume fraction constant (= 2.© 2009 ANSYS.. and its subsidiaries and affiliates.. Its unit quantity is specific-heat. Gas Constant (R) (in the Properties. Inc. category) is the production term in the secondary mixture fraction variance equation solved in the non-premixed combustion model. category) is the production term in the mixture fraction variance equation solved in the non-premixed combustion model (that is. Contains proprietary and confidential information of ANSYS. 223 . Inc. Grid.. Its unit quantity is kg/m-s.. this value corresponds to the selected phase in the Phase drop-down list... this value corresponds to the selected phase in the Phase drop-down list. is the diffusion coefficient) For more information. category) is equivalent to the diffusion coefficient in where: • • • • is the generation of energy by the solid stress tensor is the diffusion of energy ( is the collisional dissipation of energy is the energy exchange between the lth fluid or solid phase and the s th solid phase.. .. For multiphase models. All rights reserved. includes variables related to the grid.. which is in See Granular Temperature in the ANSYS FLUENT documentation for details.... includes quantities for reporting the granular temperature for each granular phase.1 .© 2009 ANSYS. Granular Conductivity (in the Properties...Variables D-I Fvar Prod (in the Pdf.. category) is the gas constant of the fluid. Release 12. Its unit quantity is For multiphase models. Granular Pressure. includes quantities for reporting the solids pressure for each granular phase ( in See Solids Pressure in the ANSYS FLUENT documentation for details. see Granular Temperature in the ANSYS FLUENT documentation. Its unit quantity is pressure. Granular Temperature. the last two terms in Fvar2 Prod (in the Pdf. All rights reserved. Release 12. Helicity (in the Velocity. or sliding meshes). category) is defined by the dot product of vorticity and the velocity vector... and is the directional acoustic intensity per unit volume of a jet defined by It is available only when the Broadband Noise Sources acoustics model is being used.. category) is the total radiation energy. is the solid angle. category) is the acoustic power for turbulent axisymmetric jets in where and are the radial and angular coordinates of the receiver location. Incident Radiation (Band n) (in the Radiation. Inc.1 . mixing planes.. is the quantity that the P-1 radiation model For the DO radiation model.Variables J-Q Grid X-Velocity. HCN Density (in the NOx. for the non-gray Internal Energy (in the Temperature. Its unit quantity is specific-energy. the incident radiation is computed over a finite number of discrete solid angles. category) are the vector components of the grid velocity for moving-grid problems (rotating or multiple reference frames. Its unit quantity is heat-flux. category) is the summation of the kinetic and potential energies of the molecules of the substance per unit volume (and excludes chemical and nuclear energies). each associated with a vector direction.© 2009 ANSYS. Its unit quantity is velocity.. that arrives at a location per unit time and per where is the radiation intensity and computes... Internal Energy is defined as .. Incident Radiation (in the Radiation. . unit area: .. The unit quantity is density... category) is the mass per unit volume of HCN. Grid Z-Velocity (in the Velocity. category) is the radiation energy contained in the wavelength band DO radiation model. The unit quantity for Incident Radiation is heat-flux. The HCN Density will appear only if you are modeling fuel NOx.. Inc... and its subsidiaries and affiliates. Variables J-Q Jet Acoustic Power (in the Acoustics. Vorticity is a measure of the rotation of a fluid element as it moves in the flow field. See Fuel NOx Formation in the ANSYS FLUENT documentation for details. 224 Contains proprietary and confidential information of ANSYS. Grid Y-Velocity. It provides insight into the vorticity aligned with the fluid stream. 1 . Contains proprietary and confidential information of ANSYS. LEE Self-Noise Z-Source (in the Acoustics. and its subsidiaries and affiliates. Laminar Flame Speed (in the Premixed Combustion. LEE Self-Noise X-Source. All rights reserved.. category) is the propagation speed of laminar premixed flames in . LEE Self-Noise Y-Source.. = turbulence time scale (s) = chemical time scale (s) Its unit quantity is velocity. reported in dB: where is the reference acoustic power ( by default). computed from where • • is the turbulence dissipation rate.. which is Release 12.. category) is the laminar diffusion coefficient of a species into the mixture. category ) are the self-noise source terms in the linearized Euler equation for the acoustic velocity component. Inc. 225 .© 2009 ANSYS. Inc... Lam Diff Coef of species-n (in the Species..Variables J-Q Jet Acoustic Power Level (dB) (in the Acoustics. category) is the acoustic power for turbulent axisymmetric jets. quantity is mass-diffusivity. Its unit where: • • • • • = model constant = RMS (root-mean-square) velocity (m/s) = laminar flame speed (m/s) = molecular heat transfer coefficient of unburnt mixture (thermal diffusivity) (m^2/s) = turbulence length scale (m). It is available only when the Broadband Noise Sources acoustics model is being used.. the source terms in the equation are grouped depending on whether the mean velocity gradients are involved (shear noise or self noise). which is Release 12. which is Lilley's self-noise source term is available only when the Broadband Noise Sources acoustics model is being used.. The first two terms denoted by are often referred to as "shear-noise" source terms.. (See LEE Self-Noise X-Source for details. category ) are the shear-noise source terms in the linearized Euler equation for the acoustic velocity component. (See LEE Self-Noise X-Source for details. 226 Contains proprietary and confidential information of ANSYS. the first three terms involving turbulence are the main contributors. They are available only when the Broadband Noise Sources acoustics model is being used. since they involve the mean shear. Among them.© 2009 ANSYS.) Lilley's Self-Noise Source (in the Acoustics.1 . Inc. category) is the shear-noise source term in the linearized Lilley's equation.) LEE Total Noise X-Source. and reported separately in ANSYS FLUENT. LEE Shear-Noise Z-Source (in the Acoustics.. which is The LEE shear-noise variables are available only when the Broadband Noise Sources acoustics model is being used.. All rights reserved. and its subsidiaries and affiliates. LEE Shear-Noise Y-Source. The LEE self-noise variables are available only when the Broadband Noise Sources acoustics model is being used. The third term is often called the "self-noise" source term. Lilley's Shear-Noise Source (in the Acoustics. LEE Total Noise Y-Source. The right side of the equation can be considered as effective source terms responsible for sound generation..Variables J-Q where refers to the corresponding acoustic components. which is The total noise source term is the sum of the self-noise and shear-noise source terms. The resulting source terms in the equation are evaluated using the mean velocity field and the turbulent (fluctuating) velocity components synthesized by the SNGR method. LEE Total Noise Z-Source (in the Acoustics.. category ) are the total noise source terms in the linearized Euler equation for the acoustic velocity component. . and the prime superscript refers to the turbulent components. Inc. category) is the self-noise source term in the linearized Lilley's equation. for it involves turbulent velocity components denoted by only.. LEE Shear-Noise X-Source.. As with the LEE source terms. Mass fraction of species-n (in the Species. the mass of NO. and the mass of N2O per unit mass of the mixture (for example. Mass fraction of NH3.. 227 .. and its subsidiaries and affiliates. Mass fraction of NO.© 2009 ANSYS.... The Mass fraction of nuclei will appear only if you use the two-step soot model.. Inc. category ) is the total noise source term in the linearized Lilley's equation.. Inc. Mass fraction of soot (in the Soot. All rights reserved. category) is the number of particles per unit mass of the mixture (in units of particles x10^15/kg.. The Mass fraction of HCN and the Mass fraction of NH3 will appear only if you are modeling fuel NOx. Mass fraction of N2O (in the NOx. category) is the ratio of velocity and speed of sound. Contains proprietary and confidential information of ANSYS. See Soot Formation in the ANSYS FLUENT documentation for details. category) is the mass of soot per unit mass of the mixture (for example. category) are the mass of HCN.. Mass fraction of nuclei (in the Soot. which is The total noise source term is the sum of the self-noise and shear-noise source terms. category) the liquid fraction computed by the solidification/melting model: Mach Number (in the Velocity. Release 12.Variables J-Q Lilley's shear-noise source term is available only when the Broadband Noise Sources acoustics model is being used. category) is the mass of a species per unit mass of the mixture (for example. the mass of NH3. (See Lilley's Self-Noise X-Source for details. kg of HCN in 1 kg of the mixture)..) Lilley's Total Noise Source (in the Acoustics. kg of soot in 1 kg of the mixture). Mass fraction of HCN. kg of species in 1 kg of the mixture). (See Lilley's Self-Noise X-Source for details..1 . and is available only when the Broadband Noise Sources acoustics model is being used. See Fuel NOx Formation in the ANSYS FLUENT documentation for details..) Liquid Fraction (in the Solidification/Melting. See Soot Formation in the ANSYS FLUENT documentation for details... ... Mole fraction of HCN.. See Postprocessing for Time-Dependent Problems in the ANSYS FLUENT documentation for details.. Mole fraction of species-n (in the Species. Release 12. Mole fraction of NO. category) is the time-averaged value of a solution variable (for example. Its unit quantity is concentration... category) is the normalized (dimensionless) coordinate that follows the flow path from inlet to outlet. category) is the variance of the mixture fraction solved for in the non-premixed combustion model.. . NO. Meridional Coordinate (in the Grid. category) is the transported quantity model: that is solved for in the Spalart-Allmaras turbulence where is the production of turbulent viscosity and is the destruction of turbulent viscosity that occurs and are constants and $\nu$ is in the near-wall region due to wall blocking and viscous damping.Variables J-Q Mean quantity-n (in the Unsteady Statistics. All rights reserved. Mole fraction of NH3. See Fuel NOx Formation in the ANSYS FLUENT documentation for details. The Mole fraction of HCN and the Mole fraction of NH3 will appear only if you are modeling fuel NOx.. Inc. Mole fraction of soot (in the Soot. is given by and Its unit quantity is viscosity. Inc.. The turbulent viscosity.. (See Definition of the Mixture Fraction in the ANSYS FLUENT documentation. Its value varies from 0 to 1. Mole fraction of N2O (in the NOx. 228 Contains proprietary and confidential information of ANSYS. is a user-defined source term. is computed directly from this quantity using the relationship given by where the viscous damping function. Mixture Fraction Variance (in the Pdf. the molecular kinematic viscosity. category) is the moles per unit volume of a species.. NH3.© 2009 ANSYS.. This is the second conservation equation (along with the mixture fraction equation) that the non-premixed combustion model solves.) Modified Turbulent Viscosity (in the Turbulence... category) is the number of moles of a species in one mole of the mixture. and N2O in one mole of the mixture.. Molar Concentration of species-n (in the Species. and its subsidiaries and affiliates.1 . category) is the number of moles of soot in one mole of the mixture. . category) are the number of moles of HCN. Static Pressure). See Preconditioning in the ANSYS FLUENT documentation for details. Phases. category) is the ratio .... which is described in Modeling Non-Premixed Combustion in the ANSYS FLUENT documentation. The unit quantity for each is density. See Fuel NOx Formation in the ANSYS FLUENT documentation for details. .... NO and N2O. Partition Boundary Cell Distance (in the Grid. For multiphase models... 229 . and its subsidiaries and affiliates. Molecular Viscosity (in the Properties. The NH3 Density will appear only if you are modeling fuel NOx.. contains quantities related to the NOx model. It gives a measure of the number of messages that will have to be generated for parallel processing. Inc.. Pressure. includes quantities related to a normal force per unit area (the impact of the gas molecules on the surfaces of a control volume). Its value varies from 0 to 1.. which is described in Modeling Premixed Combustion in the ANSYS FLUENT documentation.. See NOx Formation in the ANSYS FLUENT documentation for details about this model. category) is the laminar viscosity of the fluid... Pressure Coefficient (in the Pressure. category) is the smallest number of cells which must be traversed to reach the nearest partition (interface) boundary. NOx. All rights reserved.. Partition Neighbors (in the Cell Info.Variables J-Q Molecular Prandtl Number (in the Properties. Viscosity.. category) is a dimensionless parameter defined by the equation Release 12. category) is the number of adjacent partitions (that is. Premixed Combustion.... contains quantities related to the non-premixed combustion model.© 2009 ANSYS.....1 . For granular phases. N2O Density (in the NOx. category) is the reference velocity used in the coupled solver's preconditioning algorithm. Pitchwise Coordinate (in the Grid. this is equivalent to the solids shear viscosity in NH3 Density. Pdf.. this value corresponds to the selected phase in the Phase drop-down list. Contains proprietary and confidential information of ANSYS.. NO Density. Preconditioning Reference Velocity (in the Velocity. contains quantities related to the premixed combustion model. those that share at least one partition boundary face (interface)). See Modeling Multiphase Flows in the ANSYS FLUENT documentation for details. is defined by the ratio of shear stress to the rate of shear. contains quantities for reporting the volume fraction of each phase. Inc. category) is the normalized (dimensionless) coordinate in the circumferential (pitchwise) direction.. Its unit quantity is viscosity. category) are the mass per unit volume of NH3. Rate of Prompt NO (in the NOx. 230 Contains proprietary and confidential information of ANSYS. category) is the rate of formation of NO due to the reburn pathway only (available only when reburn pathway is active). Inc. category) is a normalized mass fraction of the combustion products ( or unburnt mixture products ( = 0). Progress Variable (in the Premixed Combustion. Variables R Rate of NO (in the NOx. Its unit quantity is turb-kinetic-energy-production. . category) is the rate of production of turbulence kinetic energy (times density).. thermal.). category) is the overall rate of formation of NO due to all active NO formation pathways (for example. Product Formation Rate . All rights reserved....Variables R where is the static pressure. Its unit quantity is time-inverse. Rate of Reburn NO (in the NOx.© 2009 ANSYS.. category) is the rate of formation of NO due to the N2O pathway only (available only when N2O pathway is active). and term (s^-1).. etc. and velocity are defined in the Reference Values (in the Premixed Combustion.... and its subsidiaries and affiliates.. category) is the rate of formation of NO due to the prompt pathway only (available only when prompt pathway is active). includes material property quantities for fluids and solids... Sct = turbulent Schmidt number. Rate of Nuclei (in the Soot.1 ... Inc. = equilibrium mass fraction of product species Properties. . = reaction progress source Production of k (in the Turbulence.. The reference pressure. density. category) is the source term in the progress variable transport equation ( in where = mean reaction progress variable. Rate of N2OPath NO (in the NOx. this value corresponds to the selected phase in the Phase drop-down list.. = mass fraction of product species . and is the reference dynamic pressure defined by panel. For multiphase models. as defined by = 1) where = number of products.. prompt.. is the reference pressure. Release 12. category) is the overall rate of formation of nuclei. includes quantities related to radiation heat transfer. Rate of Reaction-n (in the Reactions.. category) is the overall rate of formation of soot mass.. For the eddy-dissipation model.. For multiphase models. Inc. It is calculated by the solver according to the specified radiation model.. Radiation. Reactions. category) is the rate of formation of NO due to user defined rates only (available only when UDF rates are added)... Radial Velocity (in the Velocity. category) is the radial-direction component of the pull velocity for the solid material in a continuous casting process. Radial-Wall Shear Stress (in the Wall Fluxes.Variables R Rate of SNCR NO (in the NOx. category) is the length of the radius vector in the polar coordinate system. category) is the rate of radiation heat transfer through the control surface. Radial Coordinate (in the Grid. Rate of Fuel NO (in the NOx..... See Modeling Species Transport and Finite-Rate Chemistry in the ANSYS FLUENT documentation for information about modeling finite-rate reactions.. category) is the quantity . The radius vector is defined by a line segment between the node and the axis of rotation. The unit quantity for Radial Coordinate is length. For the finite-rate/eddy-dissipation model. the value is equivalent to the Turbulent Rate of Reaction-n. For the finite-rate model.. You can define the rotational axis in the Fluid panel. it is the lesser of the two. Rate of Thermal NO (in the NOx.. Radiation Heat Flux (in the Wall Fluxes. defined by where is the Incident Radiation...... this value corresponds to the selected phase in the Phase drop-down list. Release 12. category) is the rate of formation of NO due to the fuel pathway only (available only when fuel pathway is active). See Velocity Reporting Options in the ANSYS FLUENT documentation. category) is the component of velocity in the radial direction. category) is the rate of formation of NO due to the SNCR pathway only (available only when SNCR pathway is active).1 . See Modeling Radiation in the ANSYS FLUENT documentation. (See Velocity Reporting Options in the ANSYS FLUENT documentation for details.. Rate of Soot (in the Soot. Rate of USER NO (in the NOx. category) is the radial component of the force acting tangential to the surface due to friction.. The unit quantity for Radiation Heat Flux is heat-flux. 231 . and heat flux into the domain is positive... category) is the rate of formation of NO due to the thermal pathway only (available only when thermal pathway is active). The unit quantity for Radiation Temperature is temperature. includes quantities related to finite-rate reactions.© 2009 ANSYS. All rights reserved. Inc. category) is the effective rate of progress of the nth reaction. Radial Pull Velocity (in the Solidification/Melting. Its unit quantity is velocity..) The unit quantity for Radial Velocity is velocity.. Heat flux out of the domain is negative. Contains proprietary and confidential information of ANSYS. Radiation Temperature (in the Radiation. Its unit quantity is pressure.. and its subsidiaries and affiliates.. the value is the same as the Arrhenius Rate of Reaction-n... See Specular Semi-Transparent Walls in the ANSYS FLUENT documentation for details. See Velocity Reporting Options in the ANSYS FLUENT documentation for details...286 K = -7.0940980 E10^-3 = -4. Inc.3999300 E10^-3 = 2. category) is the amount of solar heat flux reflected by a semi-transparent wall for a visible or infrared (IR) radiation.089 MPa = 647. Inc. ANSYS FLUENT computes the saturation pressure.Variables R Reflected Radiation Flux (Band-n) (in the Wall Fluxes. 232 Contains proprietary and confidential information of ANSYS..1 . Refractive Index (in the Radiation. Reflected Visible Solar Flux.4192420 = 2.2186840 E10^-4 • • = 0. . .6856350 E10^-3 = 1. category) is the amount of radiative heat flux reflected by a semi-transparent wall for a particular band of radiation.. from the equation where: • • • • • • • • • • = 22..15 K Relative Length Scale (DES) (in the Turbulence.. The unit quantity for Relative Axial Velocity is velocity.01 = 338. Its unit quantity is heat-flux.. category) is the ratio of the partial pressure of the water vapor actually present in an air-water mixture to the saturation pressure of water vapor at the mixture temperature.. Relative Humidity (in the Species... category) is a nondimensional parameter defined as the ratio of the speed of light in a vacuum to that in a material. All rights reserved. category) is the axial-direction component of the velocity relative to the reference frame motion..5206580 E10^-3 = -5.© 2009 ANSYS.. and its subsidiaries and affiliates. category) is defined by Release 12.1552860 E10^-1 = 8. Reflected IR Solar Flux (in the Wall Fluxes.9721000 E10^-1 = -1. Relative Axial Velocity (in the Velocity. For simple rotation.. (See Velocity Reporting Options in the ANSYS FLUENT documentation for details. category) is the nondimensional ratio of the relative velocity and speed of sound..) The unit quantity for Relative Total Temperature is temperature. Relative Total Pressure (in the Pressure. Relative Swirl Velocity (in the Velocity. and is defined as Its unit quantity is angle. The unit quantity for Relative Swirl Velocity is velocity. Contains proprietary and confidential information of ANSYS.) The unit quantity for these variables is velocity. category) is the stagnation temperature computed using relative velocities instead of absolute velocities... The relative velocity ( ) is the difference between the absolute velocity ( ) and the grid velocity.. 233 .. for incompressible flows the dynamic pressure would be computed using the relative velocities. category) is the tangential-direction component of the velocity relative to the reference frame motion. (See Velocity Reporting Options in the ANSYS FLUENT documentation for details.) The unit quantity for Relative Tangential Velocity is velocity. All rights reserved.1 . y-.... and is an LES-based length scale. Relative X Velocity. and its subsidiaries and affiliates... (See Velocity Reporting Options in the ANSYS FLUENT documentation for more information about relative velocities. Relative Z Velocity (in the Velocity.. Relative Velocity Magnitude (in the Velocity. All of the cells inside the domain in which belong to the LES region. Relative Tangential Velocity (in the Velocity. Inc.) The unit quantity for Relative Total Pressure is pressure. category) is the radial-direction component of the velocity relative to the reference frame motion. category) is the stagnation pressure computed using relative velocities instead of absolute velocities. See Velocity Reporting Options in the ANSYS FLUENT documentation for details. the relative velocity is defined as where is the angular velocity of a rotating reference frame about the origin and is the position vector.. Relative Mach Number (in the Velocity.© 2009 ANSYS.) The unit quantity for Relative Velocity Magnitude is velocity. (See Velocity Reporting Options in the ANSYS FLUENT documentation for more information about relative velocities. that is. and z-direction components of the velocity relative to the reference frame motion... See Velocity Reporting Options in the ANSYS FLUENT documentation for details. (See Velocity Reporting Options in the ANSYS FLUENT documentation.. Relative Y Velocity.. contains different quantities for the pressure-based and density-based solvers: Release 12.. and all of the cells inside the domain in which belong to the RANS region.. category) are the x-.Variables R where is an RANS-based length scale. Residuals. in an axisymmetric swirling flow. Relative Radial Velocity (in the Velocity. Inc.) The unit quantity for Relative Radial Velocity is velocity. Relative Velocity Angle (in the Velocity.. category) is similar to the Velocity Angle except that it uses the relative tangential velocity. Relative Total Temperature (in the Temperature. category) is the tangential-direction component of the velocity relative to the reference frame motion. category) is the magnitude of the relative velocity vector instead of the absolute velocity vector. See the separate UDF manual for more information about user-defined scalars. and species. as described in Postprocessing Residual Values in the ANSYS FLUENT documentation. 234 Contains proprietary and confidential information of ANSYS. Release 12.. .. temperature. and dissipation contributions.. and oxidant mass fractions. Its unit quantity is time-inverse.. is the relative velocity magnitude. category) is the mean ratio of the secondary stream mass fraction to the sum of the fuel. secondary stream.. face-based dissipation operator. residuals).1 . Static Pressure). • RMS quantity-n (in the Unsteady Statistics. Sensible Enthalpy (in the Temperature. category) is the value of the nth scalar quantity you have defined as a user-defined scalar... Secondary Mean Mixture Fraction (in the Pdf. viscous... category) is defined as where velocity is the enthalpy.Variables S • In the density-based solvers. See Postprocessing for Time-Dependent Problems in the ANSYS FLUENT documentation for details.. and is the magnitude of the rotational Variables S Scalar-n (in the User Defined Scalars. Secondary Mixture Fraction Variance (in the Pdf. this quantity should be small compared to the average mass flow rate. Corrections are the changes in the variables between the current and previous iterations and residuals are computed by dividing a cell's correction by its physical time step.. The total residual for each variable is the summation of the Euler. In the pressure-based solver. Rothalpy (in the Temperature. as well as the time rate of change of the corrections to these primitive variables for the current iteration (that is. It is the secondary-stream conserved scalar that is calculated by the non-premixed combustion model. It is defined as where is the mixture fraction and is a representative diffusion coefficient (see The Flamelet Concept in the ANSYS FLUENT documentation for details). Scalar Dissipation (in the Pdf.. category) is the property of a medium that describes the amount of scattering of thermal radiation per unit path length for propagation in the medium. category) is the root mean squared value of a solution variable (for example.© 2009 ANSYS. and its subsidiaries and affiliates. . It can be interpreted as the inverse of the mean free path that a photon will travel before undergoing scattering (if the scattering coefficient does not vary along the path).. Inc. this category includes the corrections to the primitive variables pressure. See Definition of the Mixture Fraction in the ANSYS FLUENT documentation. The dissipation components are the vector components of the flux-like. At convergence.. Scattering Coefficient (in the Radiation. only the Mass Imbalance in each cell is reported (unless you have requested others.. category) is one of two parameters that describes the species mass fraction and temperature for a laminar flamelet in mixture fraction spaces. The unit quantity for Scattering Coefficient is length-inverse. velocity. category) is the variance of the secondary stream mixture fraction that is solved for in the non-premixed combustion model.. category) is available when any of the species models are active and displays only the thermal (sensible) enthalpy. All rights reserved. Inc. See Definition of the Mixture Fraction in the ANSYS FLUENT documentation. Inc. category) is the thermodynamic property of specific heat at constant pressure.. All rights reserved. contains quantities related to the Soot model. It is computed from .... Species.Variables S Skin Friction Coefficient (in the Wall Fluxes. from hub to casing. category) is the mass per unit volume of soot. Solidification/Melting. Its unit quantity is velocity. which is described in Soot Formation in the ANSYS FLUENT documentation.. See Fuel NOx Formation in the ANSYS FLUENT documentation for details. category) is the rate of solar heat transfer through the control surface. Its value varies from 0 to 1. Contains proprietary and confidential information of ANSYS. category) is the source term in each of the species transport equations due to reactions. includes quantities related to species transport and reactions. category) is the rate of dissipation of turbulence kinetic energy in unit volume and time. Inc.... Specific Dissipation Rate (Omega) (in the Turbulence.. species-n Source Term (in the Species. contains quantities related to solidification and melting. Soot Density (in the Soot.. category) is the ratio of specific heat at constant pressure to the specific heat at constant volume..... 235 . Soot. For multiphase models. category) is the normalized (dimensionless) coordinate in the spanwise direction. this value corresponds to the selected phase in the Phase drop-down list. while the stored cell partition (the last partition performed) is used when you save a case file.. The unit quantity is always kg/m^3-s. Specific Heat Ratio (gamma) (in the Properties.. category) is a nondimensional parameter defined as the ratio of the wall shear stress and the reference dynamic pressure where is the wall shear stress. See Partitioning the Grid Manually in the ANSYS FLUENT documentation for more information. the partition ID can be used to determine the extent of the various groups of cells... category) is the acoustic speed. and and are the reference density and velocity defined in the Reference Values panel. category) is an integer identifier designating the partition to which a particular cell belongs. Spanwise Coordinate (in the Grid. Its unit quantity is specific-heat.. It is defined as the rate of change of enthalpy with temperature while pressure is held constant.© 2009 ANSYS.1 . Specific Heat (Cp) (in the Properties.. In problems in which the grid is divided into multiple partitions to be solved on multiple processors using the parallel version of ANSYS FLUENT. Solar Heat Flux (in the Wall Fluxes.... Release 12.. Stored Cell Partition (in the Cell Info. and its subsidiaries and affiliates.. The active cell partition is used for the current calculation. Sound Speed (in the Properties. Heat flux out of the domain is negative and heat flux into the domain is positive.. The unit quantity is density. Its unit quantity is time-inverse. The accuracy of the stream function calculation is determined by the text command /display/set/n-stream-func. ... is defined as ..© 2009 ANSYS. category) relates shear stress to the viscosity.. and its subsidiaries and affiliates. the strain rate. Stream Function (in the Velocity. Static Temperature (in the Temperature. It is a gauge pressure expressed relative to the prescribed operating pressure. which is in where erfc is the complementary error function. Its unit quantity is pressure. See Calculations in the ANSYS FLUENT documentation.. A streamline is a line that is tangent to the velocity vector of the flowing fluid. category) is a nondimensional parameter that is defined as the probability of unquenched flamelets. this value corresponds to the selected phase in the Phase drop-down list. In 3D Cartesian coordinates. Stretch Factor (in the Premixed Combustion. Note that Static Temperature will appear in the Premixed Combustion.Variables S Static Pressure (in the Pressure... Strain Rate (in the Derivatives. Also called the shear rate ( in ). and Premixed Combustion. . For multiphase models. 236 Contains proprietary and confidential information of ANSYS. All rights reserved. category) is the static pressure of the fluid. the strain rate is related to the second invariant of the rate-of-deformation tensor Its unit quantity is time-inverse.1 . is defined such that where is constant along a streamline and the difference between constant values of stream function defining two streamlines is the mass rate of flow between the streamlines.. category) is formulated as a relation between the streamlines and the statement of conservation of mass.. For a 2D planar flow. category only for adiabatic premixed combustion calculations. Inc. Its unit quantity is temperature.. is the standard deviation of the distribution of : Release 12. Inc... .. The absolute pressure is the sum of the Static Pressure and the operating pressure. categories) is the temperature that is measured moving with the fluid. the stream function.. Release 12. Its unit quantity is turbulent-kinetic-energy. The isotropic part of the subgrid-scale stresses is not modeled. It expresses the proportionality between the anisotropic part of the subgrid-scale stress tensor and the rate-of-strain tensor where is the subgrid-scale turbulent viscosity. value of around 0.. and is the default value in ANSYS FLUENT.. Subgrid Kinetic Energy (in the Turbulence. defined by is the rate-of-strain tensor for the resolved scale Its unit quantity is viscosity.1 . but added to the filtered static pressure term. calculated using the LES turbulence model. All rights reserved. is the Kolmogorov micro-scale. is the turbulent integral length scale. category) is the turbulence kinetic energy per unit mass of the unresolved eddies. Lilly derived a value of 0. Inc. It is defined as . The default value of 0.© 2009 ANSYS. which is the most serious shortcoming of this simple model. category) is the turbulent (dynamic) viscosity of the fluid calculated using the LES turbulence model. category) is a mixing length for subgrid scales of the LES turbulence model.26 for is suitable for most premixed flames. for homogeneous isotropic turbulence in the inertial subrange... Subgrid Turbulent Viscosity (in the Turbulence. and (measured in turbulent non-reacting flows) is the turbulence dissipation rate at the critical rate of strain: Subgrid Filter Length (in the Turbulence..Variables S is the stretch factor coefficient for dissipation pulsation. and has to be reduced in such regions. is the Smagorinsky constant. is the distance to the closest wall.17 for this value was found to cause excessive damping of large-scale fluctuations in the presence of mean shear and in transitional flows as near solid boundary. is the volume of the computational cell. Contains proprietary and confidential information of ANSYS. 237 . Nonetheless. and its subsidiaries and affiliates.1 has been found to yield the best results for a wide range of flows. In short.. is not an universal constant. which is defined as in where and is the von Kármán constant. However. Inc. .. Surface Coverage of species-n (in the Species. Surface Heat Transfer Coef. Surface dpdt RMS (in the Acoustics.. Surface Acoustic Power Level (dB) (in the Acoustics. (in the Wall Fluxes. category) is used to view the distribution of surface clusters in the domain. category) is the Acoustic Power per unit area generated by boundary layer turbulence.© 2009 ANSYS. Surface Incident Radiation (in the Wall Fluxes. is the wall temperature. and wall shear.. and its subsidiaries and affiliates.Variables S Subgrid Turbulent Viscosity Ratio (in the Turbulence. and represented in dB as described in Surface Acoustic Power. category) is the net incoming radiation heat flux on a surface.. Release 12. category) is the amount of a surface species that is deposited on the substrate. All rights reserved... Inc. Its unit quantity is heat-flux.. dissipation rate.coefficient. Its unit quantity is mass-flux. Each cluster has a unique integer number (ID) associated with it. Surface Cluster ID (in the Radiation. Surface Deposition Rate of species-n (in the Species...) It is available only when the Broadband Noise Sources acoustics model is being used.... category) is the amount of a surface species that is deposited on the substrate at a specific point in time. Note that is a constant value that should be representative of the problem. as defined in ANSYS FLUENT. Surface Acoustic Power (in the Acoustics.1 . Its unit quantity is the heat-transfer. calculated using the LES turbulence model. . Its unit quantity is power per area.. The mean-square time derivative of the surface pressure and the correlation area are further approximated in terms of turbulent quantities like turbulent kinetic energy. category). category) is the ratio of the subgrid turbulent viscosity of the fluid to the laminar viscosity. Inc.. category) is the Acoustic Power per unit area generated by boundary layer turbulence which can be interpreted as the local contribution per unit surface area of the body surface to the total acoustic power. It is available only when the Broadband Noise Sources acoustics model is being used. category) is the RMS value of the time-derivative of static pressure ( when the Ffowcs-Williams & Hawkings acoustics model is being used... is given by the equation ). and is the reference temperature defined in the Reference Values panel.. It is available where is the combined convective and radiative heat flux. ANSYS FLUENT reports the acoustic surface power defined by the equation both in physical ( ) and dB units. 238 Contains proprietary and confidential information of ANSYS. Variables T-Z Surface Nusselt Number (in the Wall Fluxes... category) is a local nondimensional coefficient of heat transfer defined by the equation where panel, and is the heat transfer coefficient, is the reference length defined in the Reference Values is the molecular thermal conductivity. Surface Stanton Number (in the Wall Fluxes... category) is a nondimensional coefficient of heat transfer defined by the equation where is the heat transfer coefficient, , and are reference values of density and velocity defined in the Reference Values panel, and is the specific heat at constant pressure. Swirl Pull Velocity (in the Solidification/Melting... category) is the tangential-direction component of the pull velocity for the solid material in a continuous casting process. Its unit quantity is velocity. Swirl Velocity (in the Velocity... category) is the tangential-direction component of the velocity in an axisymmetric swirling flow. See Velocity Reporting Options in the ANSYS FLUENT documentation for details. The unit quantity for Swirl Velocity is velocity. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Swirl-Wall Shear Stress (in the Wall Fluxes... category) is the swirl component of the force acting tangential to the surface due to friction. Its unit quantity is pressure. Variables T-Z Tangential Velocity (in the Velocity... category) is the velocity component in the tangential direction. (See Velocity Reporting Options in the ANSYS FLUENT documentation for details.) The unit quantity for Tangential Velocity is velocity. Temperature... indicates the quantities associated with the thermodynamic temperature of a material. Thermal Conductivity (in the Properties... category) is a parameter ( ) that defines the conduction rate through a material via Fourier's law ( ). A large thermal conductivity is associated with a good heat conductor and a small thermal conductivity with a poor heat conductor (good insulator). Its unit quantity is thermal-conductivity. Thermal Diff Coef of species-n (in the Species... category) is the thermal diffusion coefficient for the nth species in these equations: Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 239 Variables T-Z where is the mass diffusion coefficient for species in the mixture and is the thermal (Soret) diffusion coefficient. The equation above is strictly valid when the mixture composition is not changing, or when is independent of composition. See the ANSYS FLUENT documentation for more information. where is the effective Schmidt number for the turbulent flow: and is the effective mass diffusion coefficient due to turbulence. See the ANSYS FLUENT documentation for more information. where is the mass fraction of species . See the ANSYS FLUENT documentation for more information. Its unit quantity is viscosity. Time Step (in the Residuals... category) is the local time step of the cell, is time. , at the current iteration level. Its unit quantity Time Step Scale (in the Species... category) is the factor by which the time step is reduced for the stiff chemistry solver (available in the density-based solver only). The time step is scaled down based on an eigenvalue and positivity analysis. Total Energy (in the Temperature... category) is the total energy per unit mass. Its unit quantity is specific-energy. For all species models, plots of Total Energy include the sensible, chemical and kinetic energies. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Total Enthalpy (in the Temperature... category) is defined as where is the Enthalpy, as defined in where is the mass fraction of species ), and is the velocity magnitude. Its unit quantity is specific-energy. For all species models, plots of Total Enthalpy consist of the sensible, chemical and kinetic energies. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Total Enthalpy Deviation (in the Temperature... category) is the difference between Total Enthalpy and the reference enthalpy, , where is the reference enthalpy defined in the Reference Values panel. However, for non-premixed and partially premixed models, Total Enthalpy Deviation is the difference between Total Enthalpy and total adiabatic enthalpy (total enthalpy where no heat loss or gain occurs). The unit quantity for Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 240 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Variables T-Z Total Enthalpy Deviation is specific-energy. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Total Pressure (in the Pressure... category) is the pressure at the thermodynamic state that would exist if the fluid were brought to zero velocity and zero potential. For compressible flows, the total pressure is computed using isentropic relationships. For constant , this reduces to: where is the static pressure, is the ratio of specific heats, and M is the Mach number. For incompressible , where is the local flows (constant density fluid), we use Bernoulli's equation, dynamic pressure. Its unit quantity is pressure. Total Surface Heat Flux (in the Wall Fluxes... category) is the rate of total heat transfer through the control surface. It is calculated by the solver according to the boundary conditions being applied at that surface. By definition, heat flux out of the domain is negative, and heat flux into the domain is positive. The unit quantity for Total Surface Heat Flux is heat-flux. Total Temperature (in the Temperature... category) is the temperature at the thermodynamic state that would exist if the fluid were brought to zero velocity. For compressible flows, the total temperature is computed from the total enthalpy method (specified in the Materials panel). For incompressible flows, the total temperature using the current is equal to the static temperature. The unit quantity for Total Temperature is temperature. Transmitted Radiation Flux (Band-n) (in the Wall Fluxes... category) is the amount of radiative heat flux transmitted by a semi-transparent wall for a particular band of radiation. Its unit quantity is heat-flux. Transmitted Visible Solar Flux, Transmitted IR Solar Flux (in the Wall Fluxes... category) is the amount of solar heat flux transmitted by a semi-transparent wall for a visible or infrared radiation. Turbulence... includes quantities related to turbulence. See Modeling Turbulence in the ANSYS FLUENT documentation. Turbulence Intensity (in the Turbulence... category) is the ratio of the magnitude of the RMS turbulent fluctuations to the reference velocity: where is the turbulence kinetic energy and is the reference velocity specified in the Reference Values panel. The reference value specified should be the mean velocity magnitude for the flow. Note that turbulence intensity can be defined in different ways, so you may want to use a custom field function for its definition. See Custom Field Functions in the ANSYS FLUENT documentation for more information. Turbulent Dissipation Rate (Epsilon) (in the Turbulence... category) is the turbulent dissipation rate. Its unit quantity is turbulent-energy-diss-rate. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Turbulent Flame Speed (in the Premixed Combustion... category) is the turbulent flame speed computed by ANSYS FLUENT using = Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 241 Variables T-Z which is equal to where • • • • • • • = model constant = RMS (root-mean-square) velocity (m/s) = laminar flame speed (m/s) = molecular heat transfer coefficient of unburnt mixture (thermal diffusivity) (m^2/s) = turbulence length scale (m) = turbulence time scale (s) = chemical time scale (s) (See Laminar Flame Speed for details.) Its unit quantity is velocity. Turbulent Kinetic Energy (k) (in the Turbulence... category) is the turbulence kinetic energy per unit mass defined as Its unit quantity is turbulent-kinetic-energy. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Turbulent Rate of Reaction-n (in the Reactions... category) is the rate of progress of the nth reaction computed by or where: • • • • is the mass fraction of any product species, is the mass fraction of a particular reactant, is an empirical constant equal to 4.0 is an empirical constant equal to 0.5 Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 242 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Variables T-Z For the "eddy-dissipation" model, the value is the same as the Rate of Reaction-n. For the "finite-rate" model, the value is zero. Turbulent Reynolds Number (Re_y) (in the Turbulence... category) is a nondimensional quantity defined as where is turbulence kinetic energy, is the distance to the nearest wall, and is the laminar viscosity. Turbulent Viscosity (in the Turbulence... category) is the turbulent viscosity of the fluid computed using the turbulence model. Its unit quantity is viscosity. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Turbulent Viscosity Ratio (in the Turbulence... category) is the ratio of turbulent viscosity to the laminar viscosity. udm-n (in the User Defined Memory... category) is the value of the quantity in the nth user-defined memory location. Unburnt Fuel Mass Fraction (in the Premixed Combustion... category) is the mass fraction of unburnt fuel. This function is available only for non-adiabatic models. Unsteady Statistics... includes mean and root mean square (RMS) values of solution variables derived from transient flow calculations. User Defined Memory... includes quantities that have been allocated to a user-defined memory location. See the separate UDF Manual for details about user-defined memory. User-Defined Scalars... includes quantities related to user-defined scalars. See the separate UDF Manual for information about using user-defined scalars. UU Reynolds Stress (in the Turbulence... category) is the UV Reynolds Stress (in the Turbulence... category) is the UW Reynolds Stress (in the Turbulence... category) is the stress. stress. stress. Variance of Species (in the NOx... category) is the variance of the mass fraction of a selected species in the flow field. It is calculated from where the constants , , and take the values 0.85, 2.86, and 2.0, respectively. See the ANSYS FLUENT documentation for more information. Variance of Species 1, Variance of Species 2 (in the NOx... category) are the variances of the mass fractions of the selected species in the flow field. They are each calculated from the same equation as in Variance of Species. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 243 Variables T-Z Variance of Temperature (in the NOx... category) is the variance of the normalized temperature in the flow field. It is calculated from the same equation as in Variance of Species. Velocity... includes the quantities associated with the rate of change in position with time. The instantaneous velocity of a particle is defined as the first derivative of the position vector with respect to time, velocity vector, . , termed the Velocity Angle (in the Velocity... category) is defined as follows: For a 2D model, For a 2D or axisymmetric model, For a 3D model, Its unit quantity is angle. Velocity Magnitude (in the Velocity... category) is the speed of the fluid. Its unit quantity is velocity. For multiphase models, this value corresponds to the selected phase in the Phase drop-down list. Volume fraction (in the Phases... category) is the volume fraction of the selected phase in the Phase drop-down list. Vorticity Magnitude (in the Velocity... category) is the magnitude of the vorticity vector. Vorticity is a measure of the rotation of a fluid element as it moves in the flow field, and is defined as the curl of the velocity vector: VV Reynolds Stress (in the Turbulence... category) is the VW Reynolds Stress (in the Turbulence... category) is the stress. stress. Wall Fluxes... includes quantities related to forces and heat transfer at wall surfaces. Wall Func. Heat Tran. Coef. is defined by the equation Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 244 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Contains proprietary and confidential information of ANSYS. and its subsidiaries and affiliates.© 2009 ANSYS.. Inc. Its unit quantity is pressure.Variables T-Z where is the specific heat. Note that wall thermal boundary conditions are applied on the Inner Surface: Release 12.. All rights reserved.. Wall Temperature (Inner Surface) (in the Temperature. is the turbulence kinetic energy at point . this value corresponds to the selected phase in the Phase drop-down list. and is defined in See the ANSYS FLUENT documentation for more information. Wall Temperature (Outer Surface) (in the Temperature. Inc.1 .. Note that wall thermal boundary conditions are applied on this surface: The unit quantity for Wall Temperature (Inner Surface) is temperature. 245 .. category) is the temperature on the inner surface of a wall (corresponding to the side of the wall surface away from the adjacent fluid or solid cell zone). Wall Shear Stress (in the Wall Fluxes. For multiphase models.. category) is the force acting tangential to the surface due to friction. category) is the temperature on the outer surface of a wall (corresponding to the side of the wall surface toward the adjacent fluid or solid cell zone). The face area calculations are done as in X Surface Area. Wall Yplus (in the Turbulence. Release 12. is the fluid density. category) are the Cartesian coordinates in the x-axis. See Near-Wall Treatments for Wall-Bounded Turbulent Flows in the ANSYS FLUENT documentation for details.. is the distance from point to the wall. Z Surface Area (see below)..1 .. category) is a nondimensional parameter defined by the equation where is the turbulence kinetic energy at point .. Y Surface Area. WW Reynolds Stress (in the Turbulence. and is the fluid viscosity at point . X Face Area. category) is the stress. category) are the components of the boundary face area vectors stored in the adjacent boundary cells. y-axis.. See Near-Wall Treatments for Wall-Bounded Turbulent Flows in the ANSYS FLUENT documentation for details.. category) is a nondimensional parameter defined by the equation where is the friction velocity... X-Coordinate. All rights reserved. Y-Coordinate. Inc. and its subsidiaries and affiliates. Z Face Area (in the Grid. For multiphase models. this value corresponds to the selected phase in the Phase drop-down list. 246 Contains proprietary and confidential information of ANSYS. Wall Ystar (in the Turbulence. is the distance from point to the wall. and is the fluid viscosity at point .© 2009 ANSYS. The unit quantity for these variables is length. . is the fluid density. Y Face Area.. and z-axis directions respectively.Variables T-Z The unit quantity for Wall Temperature (Outer Surface) is temperature. Z-Coordinate (in the Grid. Inc.. and z components of the pull velocity for the solid material in a continuous casting process. All rights reserved.. In most circumstances. The face area calculation can be restricted to a set of zones. X Surface Area. For each boundary face zone. Z-Wall Shear Stress (in the Wall Fluxes.. Y Surface Area. category) are the components of the boundary face area vectors stored in the adjacent boundary cells. and its subsidiaries and affiliates. The face areas will be calculated only on the zones selected. Y-Wall Shear Stress. respectively. the X Surface Area.. and z-axis directions. For multiphase models. Z Pull Velocity (in the Solidification/Melting. y. Z Velocity (in the Velocity. X-Wall Shear Stress... X-Vorticity. or z) is added to the cell value of the adjacent cell.Variables T-Z except the area values in the cells with more than one boundary face are not summed to obtain the cell values. category) are the x. category) are the x. and in order to make your selection active. The surface area is accumulated from all boundary faces adjacent to the boundary cell. Note that if the Boundary Zones list is empty. Z Face Area (see above) for flux and integral calculations. these values correspond to the selected phase in the Phase drop-down list. Y Face Area. X Velocity. 247 . and z components of the vorticity vector. Release 12. Y Velocity. X Pull Velocity.© 2009 ANSYS. For multiphase models. For those cells having more than one boundary face. Z-Vorticity (in the Velocity. In the few instances where area accumulation must be avoided.. Z Surface Area (in the Grid. you can mark the zones of interest and use X Face Area. The unit quantity for these variables is pressure. Y-Vorticity.. the area value relative to the last visited face of each cell is taken as the cell value. Y Pull Velocity. The unit quantity for these variables is velocity. y. Instead.1 . y. Inc. all boundary zones will be used. y-axis. category) are the x. Inc. the cell value is the sum (accumulation) of all the boundary face area values. and z components of the force acting tangential to the surface due to friction.. the component of the face area in the relevant direction (x. you need to click the Mark button in the Boundary Adaption panel. The unit quantity for each is velocity. these values correspond to the selected phase in the Phase drop-down list.. category) are the components of the velocity vector in the x-axis.. Y Surface Area. Your zone selection can be made from the Boundary Zones list contained in the Boundary Adaption panel. Z Surface Area are used for flux and surface integration. Contains proprietary and confidential information of ANSYS. y. Inc. All rights reserved.© 2009 ANSYS. Inc. Contains proprietary and confidential information of ANSYS.Release 12. and its subsidiaries and affiliates.1 . . If multiple arguments for an action are specified. providing capabilities such as loops. all the settings for >print are read from the HARDCOPY: object. 249 . 182). 249) File Operations from the Command Editor Dialog Box (p. logic. The following CCL example demonstrates this behavior of actions: # Define settings for printing HARDCOPY: Hardcopy Format= jpg Hardcopy Filename = default. 256) Other Commands (p. Additional information on editing and creating graphics objects using the CFX Command Language in the Command Editor dialog box is available in CFX Command Language (CCL) in CFD-Post (p. However. these actions get the necessary information from a specific associated CCL singleton object. 273).1 . By default. Perl statements can be embedded in between lines of simple syntax. and its subsidiaries and affiliates. much more with any CCL input file. You do not have to precede commands with the > symbol when running in Line Interface mode. 213). they must be separated by a comma (. some actions accept a few arguments that are used to optionally override the commonly changed object settings. see Command Editor (p. Command Actions You can use command actions to edit or create graphic objects and to perform some typical actions (such as reading or creating session and state files). Inc. 259). Lines starting with the # character are not interpreted and can be used for comments. Note In addition to command action statements. usually related to the input and output of data from the system. For example. Additional information on using Line Interface mode is available in Line Interface Mode (p. • • Command actions also appear in session files (where they are also preceded by the > character). if you desire. Inc. and much. Perl. All rights reserved.). This chapter describes: • • • • Overview of Command Actions (p. When running CFD-Post in Line Interface mode. you can specify the name of the hardcopy file as an argument to >print. Many actions require additional information to perform their task (such as the name of a file to load or the type of file to create). All such actions must be preceded with the > symbol. 256) Overview of Command Actions Command action statements are used to force CFD-Post to undertake a specific task. 250) Quantitative Calculations in the Command Editor Dialog Box (p. Additional information on using Power Syntax in the Command Editor dialog box is available in Power Syntax in ANSYS CFX (p. For convenience. the CFX> command prompt is shown in a DOS window or UNIX shell. All the actions described in this section along with some additional commands can be entered at the command prompt.Chapter 17. These Power Syntax commands are preceded by the ! symbol. Contains proprietary and confidential information of ANSYS. For details on the Command Editor dialog box. You can use command action statements in a variety of areas: • You can enter command action statements into the Tools > Command Editor dialog box. CCL takes advantage of the full range of capabilities and resources from an existing programming language.jpg Image Scale = 70 White Background = Off END #Create an output file based on the settings in HARDCOPY >print Release 12.© 2009 ANSYS. Inc. If you do not explicitly set this. The -1 timestep will then be loaded.File Operations from the Command Editor Dialog Box #Create an identical output file with a different filename. some parameters may be set via optional parameters as part of the load command. 250 Contains proprietary and confidential information of ANSYS. Tip If going from a transient to steady state results file. 255) Loading a Results File You load a results file by using the >load command. Boundary. This section discusses the following actions: • • • • • • • • Loading a Results File (p. all Domain.1 . 254) Importing External File Formats (p. timestep=3 This command loads the specified results file at timestep 3. >load [filename=<filename>][timestep=<timestep>] If a timestep is not specified. >print another_file. >load filename=c:/CFX/tutorials/Buoyancy2DVMI_002. you should specify the timestep to be -1 (if this is not the current setting). >load timestep=4 This command loads timestep 4 in the existing results file. load Command Examples The following are example >load commands with the expected results. . and its subsidiaries and affiliates. you will get a warning message stating that the existing timestep does not exist. 255) Controlling the Viewer (p. The parameter settings for loading the file are read from the DATA READER object. The following option is available: • filename = <filename> Release 12. 250) Saving State Files (p. 254) Exporting Data (p. Reading Session Files >readsession [filename=<filename>] The >readsession command performs session file reading and executing. Variable objects are created.© 2009 ANSYS. When a results file is loaded.jpg File Operations from the Command Editor Dialog Box You can enter command action statements into the Tools > Command Editor dialog box. Inc. but the associated data is not actually read into the post-processor until the variables are used (load-on-demand). All rights reserved. Variables will be pre-loaded if specified in the DATA READER. and Variable objects associated with the results file are created or updated. a value of -1 is assumed (this corresponds to the Final state). 252) Creating a Hardcopy (p. 250) Reading Session Files (p.res. For simplicity. 251) Reading State Files (p. Inc.cse This command reads and execute the contents of the mysession. 251 . If the STATE singleton does not exist. Saving State Files >savestate [mode=<none | overwrite>][filename=<filename>] State files can be used to quickly load a previous state into CFD-Post. and the state information will be written to the file.cse file. The >savestate command is used to write the current CFD-Post state to a file. If no SESSION singleton exists. All rights reserved. and if the specified file exists. the executor creates a new state file. • filename = <filename> Specifies the path and name of the file that the state is to be written to. and the filename exists. and execute its contents. an error will be raised indicating that a filename must be specified. If no filename is specified. If the mode in the STATE singleton is overwrite. >readsession This command reads the session file specified in the SESSION singleton. If the STATE singleton does not exist. the values of the parameters listed after the >savestate command replaces the values stored in the STATE singleton object. readsession Command Examples The following are example >readsession commands. Release 12. the existing file will be deleted. an error will be raised indicating that a filename must be specified. For this command. the filename command parameter value replaces the session filename parameter value in the SESSION singleton. the executor creates a new state file. and if the file exists. If the mode in the STATE singleton is none. and the filename exists.1 . the STATE singleton object will be queried for the filename. it will be deleted and replaced with the latest state information. >readsession filename=mysession. an error will be raised indicating that a filename needs to be specified. If the SESSION object does not exist. The commands required to save to these files from the Command Editor dialog box are described below.Saving State Files This option specifies the filename and path to the file that should be read and executed. If a STATE singleton exists. For this command. and the expected results. and the mode command parameter value replaces the savestate mode parameter value in the STATE singleton. savestate Command Examples The following are example >savestate commands. State files can be generated manually using a text editor. Inc. If mode is overwrite. an error will be returned. then an error will be raised indicating that a filename must be specified.© 2009 ANSYS. and the expected results. Contains proprietary and confidential information of ANSYS. the values of the parameters listed after the session command replaces the values stored in the SESSION singleton object. If no filename is specified. the filename command parameter value replaces the state filename parameter value in the STATE singleton. the SESSION singleton object indicates the file to use. The >savestate action supports the following options: • mode = <none | overwrite> If mode is none. and its subsidiaries and affiliates. or from within CFD-Post by saving a state file. an error will be raised. If a SESSION singleton exists. >savestate This command writes the current state information to the filename specified in the STATE singleton. • load = <true | false> Release 12. >readstate supports the following options: • mode = <overwrite | append> If mode is set to overwrite. load=<true | false>] The >readstate command loads an CFD-Post state from a specified file. filename=mystate. >savestate filename=mystate. >savestate mode=overwrite. If the file already exists. and the current state information will be saved in its place. the file will be deleted. If the STATE singleton does not exist. the following logic will determine the final result: If the system has an equivalent object (the name and type).1 . it will be deleted. Reading State Files >readstate [mode=<overwrite | append>][filename=<filename>. If the STATE singleton does not exist. and the file already exists. the executor adds the objects saved in the state file to the objects that already exist in the system. an error will be raised indicating that a filename needs to be specified. If the system has an equivalent object in name only. If a DATA READER singleton has been stored in the state file. an error will be raised indicating that a filename needs to be specified.cst file. then the object that already exists in the system will be deleted. the command causes an error.cst file. then the system assumes a savestate mode of none. some boundaries defined may not be valid for the loaded results. If the STATE singleton does not exist. and its subsidiaries and affiliates. and the savestate mode is set to none. If the file already exists. Inc.cst This command writes the current state information to the mystate.Reading State Files >savestate mode=none This command writes the current state information to the file specified in the STATE singleton. BOUNDARY objects that are not valid for the currently loaded results file will be culled. If the STATE singleton exists. 252 Contains proprietary and confidential information of ANSYS. If the mode is set to append and the state file contains objects that already exist in the system. >savestate mode=overwrite This command writes the current state information to the file specified in the STATE singleton. Overwrite mode is the default mode if none is explicitly specified.cst This command writes the current state information to the mystate. filename=mystate. If a state file contains BOUNDARY objects. All rights reserved. Inc. and load the objects saved in the state file.cst This command writes the current state information to the mystate. and the current state information will be saved in its place. and replaced with that in the state file. the load action will be invoked to load the contents of the results file. it will be deleted. the command causes an error. and the current state information will be saved in its place. an error will be raised.© 2009 ANSYS. and behave as described above. If the savestate mode is set to overwrite. • filename = <filename> The path to the state file.cst file. If the file already exists. and the state file is appended to the current state (with no new DATA READER object). >savestate mode=none. . then the object already in the system will be modified with the parameters saved in the state file. If mode is set to append. If the file already exists. and the file already exists. the executor deletes all the objects that currently exist in the system. For this command.Reading State Files If load is set to true and a DATA READER object is defined in the state file. Default objects in the state file will only overwrite those in the system if they already exist. it remains unchanged regardless of what is in the state file. etc. then the system objects are deleted before loading the new state information. readstate Command Examples The following are example >readstate commands and their expected results. >readstate mode=overwrite. filename=mystate. The default objects in the It is modified with state file replaces the existing default objects. Inc. User objects have the same behavior as the Append/True option above. the filename command parameter value replaces the state filename parameter value in the STATE singleton. All user objects get deleted.) get deleted. Default objects in the state file that do not exist in the current state will not be created. >readstate filename=mystate.cst file are loaded into the system. Append False No objects are initially deleted. If load is set to false.cst Deletes all objects currently in the system. opens the mystate. 253 . and creates the objects as stored in the state file. All rights reserved. All default objects that exist in the state file updates the same objects in the current system state if they exist. All user objects in the state file will be created. Replace existing objects if they have the same name but different type. and the mode command parameter value replaces the readstate mode parameter value in the STATE singleton. Inc.© 2009 ANSYS. and its subsidiaries and affiliates.cst file if it exists. replaced. The loading of the It gets deleted and new results file changes the default objects (boundaries. Mode Selection Load Data Selection Overwrite True What happens to the objects? What happens to the Data Reader All user objects (planes. wireframe. Overwrite False Append True No objects are initially deleted. If a STATE singleton exists. the values of the parameters listed after the >readstate command replace the values stored in the STATE singleton object. Release 12.) including deletion of objects that are no longer relevant to the new results. etc. and what will happen based on the combination of options that are selected.cst The readstate mode parameter in the STATE singleton determines if the current objects in the system are deleted before the objects defined in the mystate. Update existing objects if they have the same name and type. If the STATE singleton does not exist. Default objects that are not explicitly modified by object definitions in the state file will have all user modifiable values reset to default values. Contains proprietary and confidential information of ANSYS. readstate Option Actions The following table describes the options. the results file will not be loaded. If it exists. • • • Be created if they have a unique name. it remains unchanged regardless of what is in the state file. then the results file will be loaded when the state file is read. User objects new value from the will: state file.1 . and the DATA READER object that currently is in the object database (if any) will not be updated. If it exists. object name=<name of object>. If the STATE singleton does not exist. Importing External File Formats Data import is controlled using the >import command.cdb) and Generic (*. There are two file types that can be imported: ANSYS (*. an error will be raised indicating that a filename must be specified.1 . and its subsidiaries and affiliates. filename The name of the file to import. object name The name to give the USER SURFACE object that is created as a result of importing the file.cst Opens the mystate. an error will be raised indicating that a filename must be specified. conserve flux=<true | false> type Indicates whether to import the file as an Ansys file or Generic file. conserve flux Boolean to indicate whether or not to ensure that the heat fluxes associated with the imported ANSYS geometry remain conservative relative to the fluxes on the associated CFD-Post Boundary. The same association is used during an ANSYS file export. are read from the HARDCOPY singleton object. This association is used during an ANSYS file import to project data from the ANSYS surface onto the CFD-Post boundary/region. The CCL options associated with the >import command are: >import type=<Ansys | Generic>. Release 12.cst file. 254 Contains proprietary and confidential information of ANSYS.© 2009 ANSYS. Creating a Hardcopy >print [<filename>] The >print command creates a file of the current viewer contents. >readstate Overwrites or appends to the objects in the system using the objects defined in the file referenced by the state filename parameter in the STATE singleton. and adds the objects defined in the file to those already in the system following the rules specified in the previous table. filename=<filename>. when data from the CFD-Post boundary/region is projected back onto the ANSYS surface. The optional argument <filename> can be used to specify the name of the output file to override that stored in HARDCOPY. Settings for output format. etc. If the STATE singleton does not exist. . Inc. filename=mystate. If the STATE singleton does not exist.Creating a Hardcopy >readstate mode=append.csv). an error will be raised indicating that a filename must be specified. All rights reserved. Inc. quality. if it exists. >readstate mode=append Appends to the objects in the system using the objects defined in the file referenced by the state filename parameter in the STATE singleton. HARDCOPY must exist before print is executed. >readstate mode=overwrite Overwrites the objects in the system STATE using the objects defined in the file referenced by the state filename parameter in the STATE singleton. boundary=<associated boundary>. boundary The name of the CFD-Post boundary/region to associate with the imported ANSYS surface. Contains proprietary and confidential information of ANSYS. The names of variables to export. locations to export. to filter the top-left viewport: VIEWER Draw All Objects=false Object Name List=Wireframe END To filter the bottom-right viewport when all four viewports are active: VIEWPORT:Viewport 2 Draw All Objects=false Object Name List=Wireframe END The following are examples of viewport layouts: Release 12. Controlling the Viewer This section describes how multiple viewports can be accessed using Command Language. For example. All rights reserved. which are numbered from 1-3 in a clockwise direction. Inc. changes should be made to the VIEWER singleton. For all other viewports. changes are made to the VIEWPORT objects.© 2009 ANSYS. etc. to modify filtering in the first viewport. For example. The first (top-left) viewport is represented by the VIEWER singleton. and its subsidiaries and affiliates. while others are VIEWPORT objects.Exporting Data Exporting Data Data export is controlled using the >export command. are defined in the EXPORT singleton object. filenames. Inc. and how they are ordered and named.1 . 255 .. the result is displayed in the Calculator Window. 256 Contains proprietary and confidential information of ANSYS. Entering >calculate <function name> will not work if required arguments are needed by the function. Inc. Inc. An error message will be displayed if the list contains any invalid object names. . 256) Viewing a Chart (p. but the deletion of valid objects in the list will still be processed. Viewing a Chart >chart <objectname> The >chart command is used to invoke the Chart Viewer and display the specified Chart object. The command must be supplied with a list of object names separated by commas. Other Commands The following topics will be discussed: • • • Deleting Objects (p.1 . Release 12. Chart objects and Chart Lines are created like other CCL objects. The >calculate command is used to perform function calculations in the Command Editor dialog box.Quantitative Calculations in the Command Editor Dialog Box Quantitative Calculations in the Command Editor Dialog Box When executing a calculation from the Command Editor dialog box.© 2009 ANSYS. 256) Turbo Post CCL Command Actions (p. and its subsidiaries and affiliates. 257) Deleting Objects >delete <objectnamelist> The >delete command can be used in the Command Editor dialog box to delete objects. All rights reserved. Typing >calculate alone performs the calculation using the parameters stored in the CALCULATOR singleton object. Inc.© 2009 ANSYS. 257 .Turbo Post CCL Command Actions Turbo Post CCL Command Actions Calculating Velocity Components >turbo more vars Issuing the >turbo more vars command is equivalent to selecting the Calculate Velocity Components in the Turbo workspace. For details. Initializing all Turbo Components >turbo init Issuing the >turbo init command is equivalent to selecting Initialize All Components from the Turbo menu. see Initialize All Components (p. Contains proprietary and confidential information of ANSYS.1 . For details. All rights reserved. see Calculate Velocity Components (p. and its subsidiaries and affiliates. 187). Release 12. Inc. 204). Contains proprietary and confidential information of ANSYS. Inc. . All rights reserved. and its subsidiaries and affiliates.Release 12.1 .© 2009 ANSYS. Inc. © 2009 ANSYS. it would be written 2**2. providing capabilities such as loops. 168). much more with any CCL input file. and much. The required argument format is: !cpPolar(<"BoundaryList">. For example. This chapter describes: • • Examples of Power Syntax (p. see Gas Compressor Performance Macro (p. Some additional. <"ReferencePressure">) !compressorPerform(<"InletLocation">. and its subsidiaries and affiliates. but in Perl. Rather than invent a new language. 2 is represented as 2^2. 259) Predefined Power Syntax Subroutines (p. <"RotationalSpeed">. Inc. <"SlicePosition">. simple embedded graphical user interfaces). Lines of Power Syntax are identified in a CCL file by an exclamation mark (!) at the start of each line. <"BladeLocation">. <"OutletLocation">. <"FluidGamma">) These subroutines are loaded when CFD-Post is launched. They become steadily more complex in the later examples.Chapter 18. more complex. Perl. <"SliceNormalAxis">. Release 12. Additional information on these macro functions is available. Perl statements can be embedded in between lines of simple syntax. You can execute these subroutines from the Command Editor dialog box the same as calling any other Power Syntax subroutine. <"PlotAxis">. simple syntax lines may refer to Perl variables and lists. logic.1 . so you do not need to execute the session files before using the functions. in CEL. <"NumBlades">. you should check a Perl reference guide. examples of Power Syntax subroutines can be found by viewing the session files used for the Macro Calculator. In between Perl lines. Important You should be wary when entering certain expressions because Power Syntax uses Perl mathematical operators. 262) 2 Examples of Power Syntax The following are some examples in which the versatility of power syntax is demonstrated. 259 . Any of the above may be included in a CCL input file or CFD-Post Session file. World Wide Web access. <"InletLocation">. Power Syntax in ANSYS CFX Programming constructs can be used within CCL for advanced usage. Inc. There are many good reference books on Perl. Contains proprietary and confidential information of ANSYS. Two examples are Learning Perl (ISBN 1-56592-042-2) and Programming Perl (ISBN 1-56592-149-6) from the O'Reilly series. <"MachineAxis">. A wide range of additional functionality is made available to expert users with the use of Power Syntax including: • • • • • • • Loops Logic and control structures Lists and arrays Subroutines with argument handling (useful for defining commonly re-used plots and procedures) Basic I/O processing System functions Many other procedures (Object programming. If you are unsure about the validity of an operator. All rights reserved. CCL takes advantage of the full range of capabilities and resources from an existing programming language. 168) and Cp Polar Plot Macro (p. These are located in CFX/etc/. For details. <"TipRadius">. "outlet").Example 1: Print the Value of the Pressure Drop Through a Pipe All arguments passed to subroutines should be enclosed in quotations. print "The pressure drop is $dp\n". and its subsidiaries and affiliates. $i++) { ! $trans = ($i+1)/$numsteps. for example Plane 1 must be passed as “Plane 1” and Eddy Viscosity should be entered as “Eddy Viscosity”. Example 1: Print the Value of the Pressure Drop Through a Pipe ! ! ! ! $Pin = massFlowAve("Pressure". !$numsteps = 10. Inc. Inc. $Pout = massFlowAve("Pressure". !for ($i=0. The next line defines a for loop that increments the variable i up to numsteps. Scalar variables (that is. All rights reserved. Release 12. . simple single-valued variables) begin with a $ symbol in Perl. The object definitions then use trans to set their transparency and then repeat.1 . The final line of Power Syntax (!}) closes the for loop.© 2009 ANSYS. $i < $numsteps. 260 Contains proprietary and confidential information of ANSYS. Any legal CFX Command Language characters that are illegal in Perl need to be enclosed in quotation marks. you determine the fraction you are along in the loop and assign it to the variable trans. # Make the outer boundaries gradually transparent in # the specified number of steps. BOUNDARY:in Visibility = 1 Transparency = $trans END BOUNDARY:out Visibility = 1 Transparency = $trans END BOUNDARY:Default Visibility = 1 Transparency = $trans END !} The first line of Power Syntax simply defines a scalar variable called numsteps. Note how Perl variables can be directly embedded into the object definitions."inlet"). Next. $dp = $Pin-$Pout. Example 2: Using a for Loop This example demonstrates using Power Syntax that wraps a for loop around some CCL Object definitions to repetitively change the visibility on the outer boundaries. Inc.-0.0.-0. All rights reserved.0.-0.0 Draw Faces = Off Draw Lines = On Line Color = 0.0.0. as shown below. Example 4: Creating a Complex Quantitative Subroutine This example is a complex quantitative subroutine that takes slices through the manifold geometry. you can execute it on its own by typing !makePlanes(). 261 .03 Normal = 1.09. in the Command Editor dialog box.1 . The subroutine will be used in the next example.0474 Normal = 1. and its subsidiaries and affiliates.0 Draw Lines = On Line Color = 1.© 2009 ANSYS.08. Inc. and computes the pressure drop through to the four exit locations.038.1.Example 3: Creating a Simple Subroutine Example 3: Creating a Simple Subroutine The following example defines a simple subroutine to make two planes at specified locations.0 END !} Although this subroutine is designed for use with the next example. ! sub manifoldCalcs{ # call the previously defined subroutine (Example 3) make the # upstream and downstream cutting planes Release 12.0 Color Mode = Variable Color Variable = Pressure Range = Local END PLANE:plane2 Option = Point and Normal Point = 0. !sub makePlanes { PLANE:plane1 Option = Point and Normal Point = 0. compares the mass flow through the two sides of the initial branch. Contains proprietary and confidential information of ANSYS. -1 Point = $Xlocs[$i].05 END ! ($Pout. You can view a list of these subroutines by entering !showSubs(). you can execute it. and its subsidiaries and affiliates. These subroutines provide access to the quantitative functionality of CFD-Post. # Set-up an array that holds the approximate X location of each # of the 4 exits.2 Plane Bound = Circular Bound Radius = 0. ! print "Total = $sum [$mfunits]\n". 262 Contains proprietary and confidential information of ANSYS.0. All rights reserved. $punits) = evaluate( "massFlowAve(Pressure)\@in1" ). The list shows all currently loaded subroutines. The list is printed to the console window. Mass Flow=$massFl [$mfunits]\n". ! @Xlocs = (0.25. Inc. if the Perl variable $verbose = 1. ! $ii = $i+1. . Predefined Power Syntax Subroutines CFD-Post provides predefined subroutines that add Power Syntax functionality. $mfunits) = evaluate( "massFlow()\@plane1" ). by typing !manifoldCalcs().1 .0. # Now calculate pressure drops and mass flows through the exits # calculate the average pressure at the inlet !($Pin. $punits) = evaluate( "massFlowAve(Pressure)\@outlet" ). so it will include any custom subroutines that you have processed in the Command Editor dialog box. in the Command Editor dialog box. in the same way as any other subroutine. For example. ! } # end loop ! print "Total Mass Flow = $sum [$mfunits]\n". ! $sum = $mass1+$mass2. in the Command Editor dialog box. ! print "Mass flow through branch 1 = $mass1 [$mfunits]\n". then the result is also printed to Release 12. ! $Dp = $Pin-$Pout.025 END PLANE:plane2 Plane Bound = Circular Bound Radius = 0. ! print "Mass flow through branch 2 = $mass2 [$mfunits]\n".025 END # Calculate mass flow through each using the predefined # 'evaluate' Power Syntax subroutine and output the results ! ($mass1. PLANE:plane1 Plane Bound = Circular Bound Radius = 0. Most of these routines provide results in a single return value.-1. ! $sum = 0. ! ($massFl) = evaluate( "massFlow()\@outlet" ).$i<4.$i++) { PLANE:outlet Option = Point and Normal Normal = 0.15. # # Bound the two planes so they each just cut one side of the branch.Predefined Power Syntax Subroutines ! makePlanes().-0. ! $sum += $massFl. We then loop over the array to move the outlet # plane and re-do the pressure drop calculation at each exit. ! ($mass2) = evaluate( "massFlow()\@plane2" ).35.0. Inc.06. ! print "At outlet \#$ii: Dp=$Dp [$punits]. !} # end subroutine After processing these commands to define the subroutine.© 2009 ANSYS.45).-0. ! for ($i=0. The following is an example: ! $lengthVal = Length("Plane 1"). Inc. separated by commas). The return values will always be in the solution units of the CFX-Solver results file. Contains proprietary and confidential information of ANSYS. even if you have changed the display units in the Edit menu. The following sections describe these predefined subroutines: • • • Power Syntax Subroutine Descriptions (p. you could use the following: ! ($value. This means that if you have a plot of temperature in degrees C on Plane 1. You should enclose all arguments within quotes to avoid making possible syntax errors.1 . ! print $lengthVal. To store return values for a subroutine that returns two variables (such as the evaluate function). For details. For details. Information on the calculations performed by the subroutines is available. see area (p.Power Syntax Subroutine Descriptions the screen. For example: real.Axis) real area("Location".© 2009 ANSYS. 150). and its subsidiaries and affiliates. 263) Power Syntax Usage (p. 166). 263) Power Syntax Subroutines (p. 263 . If any argument contains more than one word (for example. Power Syntax Subroutines area(Location. $units) = evaluate("Expression 1"). each subroutine will appear in the following format: Each of the subroutines contains an argument list (in brackets. a real number and a string. Power Syntax Usage All lines of power syntax must have an exclamation mark as the first character so that they are not treated as CCL statements. it must be within quotes. see Function Selection (p. ! print "The value of Expression 1 is $value. "Locator") will return two values. the area averaged value of temperature on Plane 1 returned by the areaAve command will still be in degrees K. Each subroutine is preceded by its return value(s). Release 12. 263) Power Syntax Subroutine Descriptions In the next section. "Axis") Returns the value of area. Inc. The statements must also end with a semi-colon. string evaluate("Expression". and the units are $units". All rights reserved. Plane 1). Some subroutines return more than one value. . 600. see areaAve (p. 264 Contains proprietary and confidential information of ANSYS. compressorPerform() This is a special macro. For details.© 2009 ANSYS. calculateUnits() string calculateUnits(function. 0. For example: compressorPerform("Inlet". "Axis") Returns the result of the variable integrated over the 2D Location. (Works only in turbo mode. "Location". "Location". 152). . ave(Variable. "X". for details.Location. see areaInt (p.2) compressorPerformTurbo() This is an internal subroutine that is used only to initialize report templates. "Axis") Returns the area-weighted average of the variable.. The function name is a required argument. 10. Inc.Location.Location) real ave("Variable". collectTurboInfo() This is an internal subroutine that is used only to initialize report templates.) calculate() void calculate(function. For details. areaInt(Variable. copyFile(FromPath. "Blade". "Outlet". 151). "Location") Returns the arithmetic average of the variable. see ave (p.) Evaluates the named function with the supplied argument list.1 . which can be followed by a variable length list of arguments. Release 12.Axis) real areaAve("Variable". 168)... Inc. 1. 151).Power Syntax Subroutines areaAve(Variable. and returns the value and units.Axis) real areaInt("Variable"..03. comfortFactors() This is an internal subroutine that is used only to initialize report templates.) Evaluates the named function with the supplied argument list. see Gas Compressor Performance Macro (p. All rights reserved.. and its subsidiaries and affiliates. calcTurboVariables() void calcTurboVariables() Calculates all 'extra' turbo variables. ToPath) A utility function for copying files. and returns the float result. For details. "Location"). For example: cpPolar("Plane 1". 153).3.1 . Contains proprietary and confidential information of ANSYS. This means that you do not have to learn any other quantitative power syntax routines described in this section. The countTrue function is valid for 1D. An example is: evaluate("areaAve(Velocity v)\@Location 1") In this case. Inc. Release 12. cpPolar() This is a special macro. "Inlet". countTrue(Expression. and its subsidiaries and affiliates. 168). The reason that the @ is escaped calling evaluate() is to avoid Perl treating it as a special character. see Cp Polar Plot Macro (p. 0. The main advantage of using evaluate is that it takes any CEL expression. "ToPath") count(Location) real count("Location") Returns the number of nodes on the location. 2D. 265 . see count (p. another subroutine is evaluated. This means that you cannot use: "2*Pressure" but you can use: "2*minVal(Pressure)\@locator 1" or "100 [m]" This is simply an alternative way of typing: ! $myVal = 2 * minVal("Pressure". Also. <=. The evaluate command takes an any expression as the argument.Power Syntax Subroutines void copyFile("FromPath". <. "X". For details. Only one expression can be evaluated each time the subroutine is executed. and 3D locations. Location) The countTrue function returns the number of mesh nodes on the specified region that evaluate to “true”. or >=. evaluate will return the result units in addition to the value. >. 153).5. where true means greater than or equal to 0. any expression that resolves to a quantity. For details. "Y". "Location" ) where "Expression" contains one of the logical operators =. see countTrue (p.string evaluate("Expression") Returns the value of the expression and the units. for details. 10000) evaluate(Expression) real. Inc. real countTrue( "Expression". or more precisely.© 2009 ANSYS. All rights reserved. Power Syntax Subroutines evaluateInPreferred(Expression) real. getChildren() SV* getChildren(objName.Axis) real force("Location". see force (p. For details. fanNoiseDefault() This is an internal subroutine that is used only to initialize report templates. All rights reserved. For details. getBladeTorqueExpr() This is an internal subroutine that is used only to initialize report templates. childType) Return the children of an object in a comma separated list. Inc. "Axis") Returns the force value."' to convert the string into an array of strings. Release 12.1 .© 2009 ANSYS. forceNorm(Location. fanNoise() This is an internal subroutine that is used only to initialize report templates. Use 'split ". see forceNorm (p. and its subsidiaries and affiliates. 154).string evaluateInPreferred("Expression") Returns the value of the expression in your preferred units. force(Location. . exprExists(Expression) bool exprExists( "Expression" ) Returns true if an expression with this name exists. this subroutine return only children of the specified type. 266 Contains proprietary and confidential information of ANSYS. getBladeForceExpr() This is an internal subroutine that is used only to initialize report templates. false otherwise. "Axis") Returns the forceNorm value. If childType is not an empty string. Inc. Preferred units are the units of the data that CFD-Post uses when information is displayed to you and are the default units when you enter information (as contrasted with units of the data that are stored in results files). Use the Edit > Options > Common > Units dialog to set your preferred units. getChildrenByCategory(Category) SV* getChildrenByCategory( "Category" ) Return the children of an object that belong to the specified category in a comma-separated list. getCCLState() This is an internal debugging call. 155).Axis) real forceNorm("Location". Power Syntax Subroutines getExprOnLocators() This is an internal subroutine that is used only to initialize report templates. getExprString(Expression) string getExprString( "Expression" ) Returns the value and the units of the expression in the form “value units”. For example: “100 m” getExprVal(Expression) real getExprVal( "Expression" ) Returns only the "value" portion of the expression (units are not included). getObjectName() string getObjectName(objPath) Extracts the name of an object from the objPath. getParameterInfo() SV* getParameterInfo(objName, paramName, infoType) Returns the requested information for a parameter of an object. getParameters() SV* getParameters(objName) Returns the parameters of an object in a comma-separated list. Use 'split ","' to convert the string into an array of strings. getTempDirectory() char getTempDirectory() Returns the temporary directory path. getType() SV* getType(objName) Returns the object type. getValue(Object Name,Parameter Name) A utility function that takes a CCL object and parameter name and returns the value of the parameter. getValue("Object Name", "Parameter Name") Returns the value stored in Parameter Name. Example 1. 2. Create a text object called Text 1. In the Text String box, enter Here is a text string. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 267 Power Syntax Subroutines 3. 4. Click Apply to create the text object. In the Command Editor dialog box, enter the following: !string = getValue( "/TEXT:Text 1/TEXT ITEM: Text Item 1", "Text String"); ! print $string; 5. Click Process, and the string will be printed to your terminal window. The same procedure can be carried out for any object. getViewArea() void getViewArea() Calculates the area of the scene projected in the view direction. Returns the area and the units. isCategory() int isCategory(objName, category) A return of 1 indicates that the object matches the passed category; 0 otherwise. Length(Location) real Length("Location") Returns the value of length. For details, see length (p. 156). Note While using this function in Power Syntax the leading character is capitalized to avoid confusion with the Perl internal command “length.” lengthAve(Variable,Location) real lengthAve("Variable", "Location") Returns the length-based average of the variable on the line locator. For details, see lengthAve (p. 156). lengthInt(Variable,Location) real lengthInt("Variable", "Location") Returns the length-based integral of the variable on the line locator. For details, see lengthInt (p. 157). liquidTurbPerformTurbo() This is an internal subroutine that is used only to initialize report templates. liquidTurbPerform() This is an internal subroutine that is used only to initialize report templates. massFlow(Location) real massFlow("Location") Returns the mass flow through the 2D locator. For details, see massFlow (p. 157). Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 268 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Power Syntax Subroutines massFlowAve(Variable,Location) real massFlowAve("Variable", "Location") Returns the calculated value of the variable. For details, see massFlowAve (p. 158). massFlowAveAbs() This is an internal subroutine that is used only to initialize report templates. massFlowInt(Variable,Location) real massFlowInt("Variable","Location") Returns the calculated value of the variable. For details, see massFlowInt (p. 160). maxVal(Variable,Location) real maxVal("Variable", "Location") Returns the maximum value of the variable at the location. For details, see maxVal (p. 161). minVal(Variable,Location) real minVal("Variable", "Location") Returns the minimum value of the variable at the location. For details, see minVal (p. 161). objectExists() int objectExists(objName) A return of 1 indicates that the object exists; 0 otherwise. probe(Variable,Location) real probe("Variable", "Location") Important This calculation should only be performed for point locators described by single points. Incorrect solutions will be produced for multiple point locators. Returns the value of the variable at the point locator. For details, see probe (p. 162). pumpPerform() This is an internal subroutine that is used only to initialize report templates. pumpPerformTurbo() This is an internal subroutine that is used only to initialize report templates. range(Variable,Location) (real, real) range("Variable", "Location") Returns the minimum and maximum values of the variable at the location. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 269 Power Syntax Subroutines reportError(String) void reportError( "String" ) Pops up an error dialog. reportWarning(String) void reportWarning( "String" ) Pops up a warning dialog. showPkgs() void showPkgs() Returns a list of packages available which may contain other variables or subroutines in Power Syntax. showSubs() void showSubs("String packageName") Returns a list of the subroutines available in the specified package. If no package is specified, CFD-Post is used by default. showVars() void showVars("String packageName") Returns a list of the Power Syntax variables and their current value defined in the specified package. If no package is specified, CFD-Post is used by default. spawnAsyncProcess() int spawnAsyncProcess(cmd, args) Spawns a forked process. sum(Variable,Location) real sum("Variable", "Location") Returns the sum of the variable values at each point on the locator. For details, see sum (p. 162). torque(Location,Axis) real torque("Location", "Axis") Returns the computed value of torque at the 2D locator about the specified axis. For details, see torque (p. 163). turbinePerform() This is an internal subroutine that is used only to initialize report templates. turbinePerformTurbo() This is an internal subroutine that is used only to initialize report templates. Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. 270 Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Power Syntax Subroutines verboseOn() Returns 1 or 0 depending if the Perl variable $verbose is set to 1. volume(Locator) real volume("Location") Returns the volume of a 3D locator. For details, see volume (p. 163). volumeAve(Variable,Location) real volumeAve("Variable", "Location") For details, see volumeAve (p. 163). volumeInt(Variable,Locator) real volumeInt("Variable", "Location") For details, see volumeInt (p. 164). Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 271 Release 12.1 - © 2009 ANSYS, Inc. All rights reserved. Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. You can cancel e mode without processing the commands by typing . Line Interface Mode This chapter contains information on how to perform typical user actions (loading. Note that once inside CFD-Post. Features Available in Line Interface Mode The following features are available in line interface mode: Viewer Hotkeys The zoom. 182). see Quantitative Calculations in the Command Editor Dialog Box (p. 249). type getstate <ObjectName>. you can enter any set of valid CCL commands. For details. Viewing All Currently Defined Objects (getstate Command) The list of all currently defined objects can be obtained using the getstate command. and its subsidiaries and affiliates. pan and other mouse actions available for manipulating the Viewer in the GUI perform identical functions in the Viewer in Line Interface mode. as some functions are object-specific) and type the command. Calculator When functions are evaluated from the command line. type calculate help at the command prompt. To call up a list of valid commands. • UNIX: Execute the command <CFXROOT>/bin/cfdpost -line at the command prompt (omitting the -line option will start the GUI mode). see Command Editor (p. file paths should contain a forward slash / (and not the backslash that is required in MS-DOS). All of the functionality of CFD-Post can be accessed when running in Line Interface mode. This can be done by entering mode con lines=X at the command prompt before entering CFD-Post. To run in Line Interface mode: • Windows: Execute the command <CFXROOT>\bin\cfdpost -line at the DOS command prompt (omitting the -line option will start the GUI mode). e must be typed (whereas this is not required in the Command Editor dialog box). type help at the command prompt. In addition to this. All rights reserved. printing. the > symbol required in the Command Editor dialog box is not needed. The commands are not processed until you leave e mode by typing . Inc. (The action commands shown in this link are preceded by a > symbol. rotate. or by reading the object definition from a session or state file. create graphical objects. To execute a hotkey command. all commands are assumed to be actions. An explanation and list of command actions are available.) You can create objects by entering the CCL definition of the object when in e mode. click once in the Viewer (or on the object. hotkeys can be used to manipulate other aspects of the Viewer. A viewer is provided in a separate window that will show the geometry and the objects that are created on the command line. when entering lines of CCL or Power Syntax. click in the Viewer to make it the active window and select the ? icon. Release 12.e.© 2009 ANSYS. You may want to change the size of the MS-DOS window to view the output from commands such as getstate. see File Operations from the Command Editor Dialog Box (p.Chapter 19. For details. 256). Line Interface mode differs from the Command Editor dialog box because Line Interface action commands are not preceded by a > symbol. For details.c. and perform quantitative calculations when running CFD-Post in Line Interface mode. providing the correct syntax is used. In Line Interface mode. for details. you are simply entering the commands that would otherwise be issued by the GUI. When in e mode. and so on). 250). 273 . In CFD-Post Line Interface mode. where X is the number of lines to display in the window.1 . You may choose a large number of lines if you want to be able to see all the output from a session (a scroll bar will appear in the DOS window). see Overview of Command Actions (p. For a list of valid calculator functions and required parameters. For a full list of all the hotkeys available. Additional information is available. and all commands that work for the Command Editor dialog box will also work in Line Interface mode. This should be omitted when entering action commands at the command prompt. All of the functionality available from the Command Editor dialog box in the GUI is available in Line Interface mode by typing enterccl or e at the command prompt. It should be noted that these are the only principal differences. To get details on a specific object. Contains proprietary and confidential information of ANSYS. the result is simply printed to standard output. Inc. In the same way. In summary. type: = Executing a UNIX Shell Command If you want to carry out a UNIX shell command. Repeating CCL Commands If you want to repeat the most recent CCL command.5 END .© 2009 ANSYS. 274 Contains proprietary and confidential information of ANSYS. The following example provides a set of commands that you could enter at the CFX> command prompt. Quitting a Command Line Interface Session To end you CFD-Post command line interface session from the command prompt.Features Available in Line Interface Mode Viewing a Chart You can view a chart object in the Chart Viewer using the chart <ChartObjectName> command. and its subsidiaries and affiliates.e CFX> quit Release 12. Inc. CFX> load filename=c:/MyFiles/StaticMixer.1 . type % directly before your command. enter: quit Example. Inc.res CFX> getstate StaticMixer Default CFX> e BOUNDARY:StaticMixer Default Visibility = On Transparency = 0. For example. %ls will list all the files in your current directory. The output written to the screen when executing these commands is not shown. . All rights reserved. 1982 3 Raw. 68.G. Inc. 277) References 41-60 (p. C. 9. B. Sarkar.. pp. 1991. 6 Schiller.. W. 1994. Bibliography This bibliography contains entries referenced in the ANSYS CFX documentation. “Modelling the pressure-strain correlation of turbulence: an invariant dynamical systems approach”. 290) References 161-180 (p. 77. All rights reserved. 288) References 141-160 (p. 2 Rhie. “Progress in the developments of a Reynolds-stress turbulence closure”. 4 Launder.. Reece. 7 Release 12. Kiel. S. L. Vol. “A Coupled Algebraic Multigrid Method for the 3D Navier-Stokes Equations”.Chapter 20. “A Numerical Study of the Turbulent Flow Past an Isolated Airfoil with Trailing Edge Separation”. • • • • • • • • • • References 1-20 (p.© 2009 ANSYS. p. 1933. Vol. M. Fluid Mechanics. A. 275 . B. VDI Zeits. “A Multigrid method Based on the Additive Correction Strategy”. 275) References 21-40 (p. 245-272. 511-537. 1975. 277. 10th GAMM Seminar. 318. pp. 293) References 181-200 (p.. T. 1986.L. Fluid Mechanics. and Rodi. pp. C. 5 Speziale. 282) References 81-100 (p. G. and Naumann.J. Inc. 279) References 61-80 (p. 295) References 1-20 1 Hutchinson. and Raithby. Contains proprietary and confidential information of ANSYS. 286) References 121-140 (p. AIAA Paper 82-0998.E. and its subsidiaries and affiliates...J.537-566. J.M.. W.1 . Numerical Heat Transfer.D. and Chow.R. J. Vol. and Gatski.. G. 284) References 101-120 (p.B. .References 1-20 Hughmark.© 2009 ANSYS.. editor.J. D.1 . D. 1981. “Multiscale model for turbulent flows”. 2003. 1219. 24(9):1541-1544. 1967.1605. and its subsidiaries and affiliates. 11 Wilcox. Inc. 32(8).. International Journal of Heat and Mass Transfer. “Wall functions for general application CFD codes”.R.R. T. F.G. 1994. “Viscous Fluid Flow”. P. 13 Launder.B. “The numerical computation of turbulent flows”. 1998. 12 Menter. and Coakley.. 3:269-289... 1598 . 9 Menter.Papailiou et al. “Multiscale model for turbulent flows”. In 24th Fluid Dynamics Conference. 15 Kader.. In AIAA 24th Aerospace Sciences Meeting. 1112-1117. ..M. All rights reserved. P. 1993. American Institute of Aeronautics and Astronautics. 10 Grotjans. 1986. 276 Contains proprietary and confidential information of ANSYS. G. AIAA-Journal. pp. 13 p. American Institute of Aeronautics and Astronautics. B.. M. F. Comp Meth Appl Mech Eng. “Temperature and concentration profiles in fully turbulent boundary layers”. B. and Menter. In K. Bradshaw. H. ECCOMAS 98 Proceedings of the Fourth European Computational Fluid Dynamics Conference. pp..R.C. 16 Huang.. 14 White. and Spalding. F.. 1991. Inc. McGraw-Hill. 8 Modest. AIChE J. Second Edition Academic Press.E. 1974.A. “Radiative Heat Transfer”. “Two-equation eddy-viscosity turbulence models for engineering applications”.A. John Wiley & Sons.. Release 12..D. F. Second Edition. 20 Lopez de Bertodano. AIChE J. 35.. “Liquid Velocity Distribution in Two-Phase Bubbly Flow”.J. M. Y. and Zuber.W. 1998. M. Lyczkowski.. D. D. “Two Fluid Model for Two-Phase Turbulent Jet”. 25. 22 Sato. R. 277 . 65-74. and J. 17 Bouillard. 1975.References 21-40 “Skin friction and velocity profile family for compressible turbulent boundary layers”. Droplet or Particulate Flows”.1 . “Porosity Distribution in a Fluidised Bed with an Immersed Obstacle”.R. N... 2. 1993. 1991. 31(9):1600-1604. Multiphase Flow. Howell. Des. 179.79. M.© 2009 ANSYS. J. “Drag Coefficient and Relative Velocity in Bubbly.. 1979. ISBN 0-89116-506-1. 1989. Academic Press. “Boundary Conditions for the Diffusion Solution of Coupled Conduction-Radiation Problems”. 843-855. Howell. NASA TN D-4618. R and J.. “Multiphase Flow and Fluidisation”.R. K. Int.and Gidaspow.. Thesis.. 23 Siegel.X. NASA Technical Note. 18 Gidaspow. “Thermal Radiation Heat Transfer”. J. M. Troy New York. Inc. M. Contains proprietary and confidential information of ANSYS. Release 12. and Sekoguchi. and its subsidiaries and affiliates. AIChE J. 24 Goldstein. 1994. All rights reserved. 19 Ishii. Inc. p. “Turbulent Bubbly Flow in a Triangular Duct”. 908-922.. Eng. 25 Raw. D. Rensselaer Polytechnic Institute. References 21-40 21 Lopez de Bertodano. Nucl. Ph. American Institute of Aeronautics and Astronautics Journal. 1989. Kothe..(1991).. D. ASME J. 1960. and its subsidiaries and affiliates.N. 876-884. “General Circulation Experiments with the Primitive Equations”. 28 Barth. and Lightfoot. Vol. 314. All rights reserved. La Canada. R. R. J. Fluids Engineering.B... A. R. F. 1992. J.C. Fluid Mech. John Wiley & Sons. and Miller. P. Rupley. D. 2000. W. J. “Transport Phenomena”.. B. Younis. 27 Brackbill. and Jesperson.J.. 30 Wilcox. “Eddy Viscosity Transport Equations and their Relation to the k − ε Model”. NV. Reno. January 15-18 1996.. AIAA Paper 89-0366. D. pp. SAND89-8009.© 2009 ANSYS. 26 Kee. E. CA 91011. Inc. Journal of Computational Physics 100:335-354.C.. 33 Menter. J. Release 12. p. Tselepidakis.. AIAA 96-0297. and Zemach. NASA Technical Memorandum 108854. C. Vol. F.. 32 Menter. 34th Aerospace and Sciences Meeting & Exhibit. 278 Contains proprietary and confidential information of ANSYS.E. “Turbulence Modelling for CFD”. pp. November 1994. Inc. Stewart. DCW Industries. 1997. B. 63-75. T. F... J. “Eddy Viscosity Transport Equations and their Relation to the k − ε Model”. Inc. “The Design and Application of Upwind Schemes on Unstructured Meshes”. M.U..1 . 119.B. “A second-moment closure study of rotating channel flow”. “A Continuum Method for Modelling Surface Tension”. 29 Bird. . 31 Launder.. R. A.. 34 Smagorinsky. D. “Chemkin -II: A Fortran Chemical Kinetics Package for the Analysis of Gas-Phase Chemical Kinetics". Sandia National Laboratories Report. 1987.E.References 21-40 “Robustness of Coupled Algebraic Multigrid for the Navier-Stokes Equations”. 183. Vol.. O. 35 Clift. U. R. 1999.. J.. Weath. All rights reserved..S. Inst. Madrid. A. E. Vol. 99-165. J. 2001. 36 Liang. pp.L. Biagioli.. L. 1155-1165.. 42 Linan.. Michaelides. “The magnitude of Basset forces in unsteady multiphase flow computations”. “Gas Premixed Combustion at High Turbulence.A. aeron. Spain. 114. and Weisenstein. 279 . “Modelling turbulent premixed combustion in the intermediate steady propagation regime”. Polifke. Turbulent Flame Closure Combustion Model”.. 120. J. Weber. W. 1978. “An efficient Computational Model for Premixed Turbulent Combustion at High Reynolds Numbers Based on a Turbulent Flame Speed Closure“. Rev. 39 Hinze.. M. Cambridge University Press. nac. “Turbulence”.E. pp. F. 43 Release 12. Esteban Terradas.L. E. 1963. pp. 38 Zimont. V. Journal of Fluids Engineering. M. pp. Vol. Inc. 1998. and Syed.. Contains proprietary and confidential information of ANSYS.. Bettelini.R. Khawar. 93.1 . Italy. 2000.L. New York. 1975. McGraw-Hill. 1992. V. Proceedings of the Mediterranean Combustion Symposium. 40 Zimont. pp.S.References 41-60 Month.A. Academic Press.CNR. Vol. W. Technical note.. U. “On the internal structure of laminar diffusion flames”.© 2009 ANSYS. “Turbulent Combustion”. Progress in Computational Fluid Dynamics. 1961. Drops and Particles”. 14-28. 37 Peters. 417-419. N. and its subsidiaries and affiliates. Inc. Grace. New York. Cambridge monographs on mechanics. V. 1.. References 41-60 41 Zimont. “Bubbles. Instituto di Richerche sulla Combustione . 526-532. Engineering for Gas Turbines and Power (Transactions of the ASME). de tec.... H. S. F. Flame.) on Combustion.. Int. 43. J. Verlag.B. Springer. New York 1967. Oct. McGraw-Hill.219-221. 48 Hottel.. 1958. pp. and Knorre. B. H. and Dibble.F.. 1971. “On Mathematical Modeling of Turbulent Combustion with Special Emphasis on Soot Formation and Combustion”. Its Physical and Practical Implications”.J. (Int. 19. R. 46 Magnussen. W. 49 Hadvig.. “Kinetics of Dispersed Carbon Formation”..References 41-60 Warnatz. 17. 1996. 1591-1605. P. “Spectral and total emissivity of water vapour and carbon dioxide”. Mass. p 719. . Vol. “Combustion”. 1989. 1974. pp. “The Eddy Dissipation Concept for Turbulent Combustion Modelling. A. U. Sixteenth Symp. 50 Leckner. and Hjertager. and its subsidiaries and affiliates. 52 Release 12. P. G.. Presented at the First Topic Oriented Technical Meeting. P. Inst. pp. 17. International Flame Research Foundation. Inc.© 2009 ANSYS.. B. “The total emissivities of luminous and non-luminous flames”.. A. B. “Radiative transfer”. The Combustion Institute. F. J. M. Fuel. 1976. 1972. T. Moscow. “Gas emissivity and absorptivity”. 280 Contains proprietary and confidential information of ANSYS. Mashgis.. and Sarofim. Comb.. 1970. The Netherlands. 33-48. J.. IJmuiden. B. and Foster. 129-135..1 . 47 Vukalovich. 253-260. 45 Tesner... Heat Mass Transfer. 51 Taylor.. pp.. 6th ed. Combustion and Flame. P. All rights reserved. “Thermodynamic Properties of Water and Steam”. 44 Magnussen. Inc. Snegirova. pp.. V. D.C. 2002. “Comments on the feasibility of LES for wings.1 . 55 Menter. Ca.J. 2002.. M. 2001. VTT Publications. Foster.References 41-60 Beer..© 2009 ANSYS. “Adaptation of Eddy-Viscosity Turbulence Models to Unsteady Separated Flow Behind Vehicles”. S. The Aerodynamics of Heavy Vehicles: Trucks. Version 2. 1st AFOSR Int... Kuntz. “Two phase model for binary liquid-solid phase change”.12.R. and Allmaras. Release 12. Argonne National Laboratory ANL-77-47. Asilomar. C. p. OH. 53 Prakash.R.2. Jou. and Kuntz. NV. Proc. 171. M. Greyden Press. and on a hybrid RANS/LES approach”. 281 . Numerical Heat Transfer. AEA Technology (Commercial). Conf. V. Reno. Parts I and II.. “Detached Eddy Simulation of Massively Separated Flows”.. “Development and Application of a Zonal DES Turbulence Model for CFX-5”. and Tavassalo. F. 58 Strelets. Inc. In Advances in DNS/LES. Waterloo. 22. Ontario. “Calculation methods of radiative heat transfer”. Colombus. CFX-Validation Report. B 15.4-8. P. M. 1977. Contains proprietary and confidential information of ANSYS. Liu & Z. M. Conf. 54 CFX Limited. F. 39th Aerospace Sciences Meeting and Exhibit.1. J. R... and Siddall. Aug.G. 57 Spalart. Liu Eds. 1996. R. HTFS Design Report No. Ruston. M. 56 Menter.-H.. 60 Manninen. All rights reserved.. C. “One-dimensional drift-flux model and constitutive equations for relative motion between phases in various two-phase flow regimes”. 1997.M. Section 4.. AIAA Paper 2001-0879. P. W.. 59 Ishii.. CFX-VAL17/0503. Inc. Strelets. M. “On the Mixture Models for Multiphase Flow”.R. 1971. Canada. Busses and Trains. and its subsidiaries and affiliates. On DNS/LES. CFX-TASCflow Theory Documentation. LA. References 61-80 References 61-80 61 Luo. “Centrifugal Compressors: A strategy for Aerodynamic Design and Analysis”. and Svendsen. M. “Mixing. C. R. and Moo-Young. AIChE Journal 42. Release 12. M.1 .M... “Mechanical and metallurgical aspects of the erosion of metals”. and Humphrey. 13...102... “Theoretical Model for Drop and Bubble Breakup in Turbulent Dispersions”. pp. on Corrosion-Erosion of Coal Conversion System Materials. H. G. transport and combustion in sprays”. 69 Bello. All rights reserved. M. pp. Vol. 68 Mijnbeek. S. Chemical Institute of Canada and Canadian Society for Chemical Engineering. “Bubble column. 62. 1485-1499. Proc. airlift reactors and other reactor designs”. Process Energy Combustion Science.L. 293-345. and its subsidiaries and affiliates. 1225 -1233.. 64 Dosanjh. and Blanch. Vol. . C.H.. “The influence of turbulence C on erosion by a particle laden fluid jet. 1985. G. “Simplified Reaction Mechanisms for the Oxidation of Hydrocarbon Fuels in Flames”.© 2009 ANSYS. H. 2000.A. W.K. 65 Aungier. F. “Bubble Coalescence and Break-Up in Air-Sparged Bubble Columns”. 31-43. 66 Westbrook. Dryer. Chapter 4.. 282 Contains proprietary and confidential information of ANSYS. Combustion Science and Technology Vol. A. V.. S. 1992. AIChE Journal 36. 1981. 27. Conf. Wear”.C. 1987. Inc. Operational Modes of Bioreactors. 573. 1984. I. ASME Press. Robinson. Canadian Journal of Chemical Engineering.. 63 Hutchings. pp. 62 Prince. 67 Faeth.M. Inc.. J.. pp. New York. NACE (1979) 393. R. Butterworth and Heinemann.. 309-330. B. and its subsidiaries and affiliates. p. J. Journal of Chemical Technology & Biotechnology..1 . P.© 2009 ANSYS. 48(3).W. 218. W. T. Huang. 74 S. A. 1997. Inc. Bagatin and M. Vol.R. T. 6. 71 Maneri.J. J. 72 Baker. 1968.. (See also Bardina. 268.E.. 1965. 521”. Eng. Industrial Engineering Chemistry Process Design and Development. “Prediction of gas hold-up and liquid velocity in airlift reactors using two-phase flow friction coefficients”. 1967. AIAA Paper 97-2121. Secunda.J. South Africa. H. G. E. Von Rosenburg. 1952. P..G. and Marshall. Industrial Engineering and Chemical Process Design and Development. “Turbulence Modeling Validation Testing and Development”.. C.References 61-80 70 García-Calvo. and Coakley. 11. McGraw-Hill. D.. American Institute of Chemical Engineers Journal. 1979. L. T. 388-396. 75 Ranz.J. 76 Bardina. J. p. R. p. “The Development of a CFD Analysis and Design Tool for Air-lift Reactors”. Vol. W.E. American Institute of Chemical Engineers Journal. P.W. All rights reserved. Gannon. P. Schlichting. 79 S. and R. S. Masi. American Institute of Chemical Engineers. D.) 77 H.E. 283 . and Hawksley. 67. 1996. “Kinetics of thermal decomposition of pulverised coal particles.G. “Turbulence Modeling Validation”. Contains proprietary and confidential information of ANSYS. Inc. C. 14. and Chao. Ubhayakar. Proceedings of the SAIChE 2000 Conference. 141.E. L. NASA Technical Memorandum 110446. 295. Release 12.. 1997. p. Vol... 73 Hughmark. pp. C.. American Institute of Chemical Engineers. Huang. Prog.. 9 p. Wiley Interscience. B. 78 Badzioch. and Coakley.G. 2000. and Mendelson. Lo.. Stickler.. and Letón. Chem. “Boundary Layer Theory”. Vol. . 2001. 1976. J. 5:507-531. Fugacities of Gaseous Solutions. “The Properties of Gases and Liquids”.. TheNetherlands. K. 87 Mei.J.. 1954. and Kwong. J. Phil. P.S.. Phelan.© 2009 ANSYS.O.. J. J.. “Shear lift force on spherical bubbles”. 1984. All rights reserved.1 . McGraw-Hill. 84 Poling. Lee. B.. The Combustion Institute. 15. and M. Chem Rev 44:233.References 81-100 “Rapid devolatilization of pulverised coal in hot combustion gases”. 62. “Applications of Kinetic Gas Theories and Multiparameter Correlation for Prediction of Dilute Gas Viscosity and Thermal Conductivity”. References 81-100 81 Sutherland.H. 23:8. Wiley. Chem. 1965.L. and its subsidiaries and affiliates. R. Fluid Mech. Inc. “Molecular Theory of Gases and Liquids”. and Starling. An Equation of State. Int.". Release 12. T.H. J. p.. . Inc.. J. and O'Connell. and Klausner.P.N. and Bartz. 1949..M. Ind. 16th Symposium (International) on Combustion. R. L. InternationalFlame Research Foundation Report F388/a/3 IJmuiden. S. Mag. 1893. Bird. New York. p. 80 Wall. “The Viscosity of Gases and Molecular Force”.. New York. Heat and Fluid Flow. G. 86 Saffman.E. p. W.B. J. “The lift on a small sphere in a slow shear flow”...F. T. 85 Redlich. 284 Contains proprietary and confidential information of ANSYS. “The prediction of scaling of burnout in swirled pulverised coal flames”. V. 82 Hirschfelder. 1976. Taylor. F. 1994.. 83 Chung. 385. O. W.. "On the Thermodynamics of Solutions. Fundam. Prausnitz.. 426.E. Eng... 22. Z. 92 CIBSE Guide A: Environmental Design CIBSE.D. 77: 3433 (1955)..B. J-M. D. R. 277-281.H.. U. Contains proprietary and confidential information of ANSYS. E. Int. 89 Krepper. 1995. A. ICMF-2004. Lippmann. J. and Shi. K. pp. 90 Burns. 1999. Gunn. Inc. Chem Eng. Hamill. J.M. 1973. Int.. E..References 81-100 88 Antal. C. J. pp. “Analysis of phase distribution in fully developed laminar bubbly two-phase flow”. in AMIFESF Workshop. 22 Suppl. 29. All rights reserved.© 2009 ANSYS. 94 Yamada. Enwald. Huggins.. R. 7. and Flaherty. 18.E.A. Moderate thermal environments . 21-66. Yokohama. H-M. 234. 97 H. Soc.S. Release 12. 2003.K.. J.. S.. Multiphase Flow. 1991. Drew.F. Lahey.T. Almstedt.. 93 ISO 7730-1984(E).. Vol. and R. Frank. Multiphase Flow.. T. Peirano and A.D. Accurate Real Gas Equation of State for Fluid Dynamic Analysis Applications”.. J. Chem. “Measurements and CFX Simulations of a bubbly flow in a vertical pipe”. and its subsidiaries and affiliates. R.. E. 95 Pitzer. “Eulerian Two-Phase Flow Theory Applied to Fluidisation”. Am. 635-652. Curl. R. Computing Methods in Two-Phase Flow. 117. Larreteguy. Data.1996. Journal of Fluids Engineering. T. and Prasser.. J..E. pp. Multiphase Flow. Int. 91 Moraga. p. E. “A Fast.1 .Determination of the PMV and PPD indices and specification of the conditions for thermal comfort 1984. P. Petersen..F. I. 96 Aungier. 2000. Japan. and D. 655. and Lahey. Th. Inc. “Drag Model for Turbulent Dispersion in Eulerian Multi-Phase Flows”. J. p. “Assessment of turbulent dispersion models for bubbly flows in the low Stokes number limit”. 285 ... 5th International Conference on Multiphase Flow. A. D. 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F. “Kinetic Theories for Granular Flow: Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flow Field”. 102 Langtry.B.© 2009 ANSYS. and its subsidiaries and affiliates..1 . Suzen. D. Lun. ASME-GT2004-53452. Fluid Mech. References 101-120 101 Menter. Huang. “Advanced Modelling of Droplet Deformation and Breakup for CFD Analysis of Mixture Preparation”. Suzen. and N. “The Effects of an Impact Velocity Dependent Coefficient of Restitution on Stresses Developed by Sheared Granular Materials”. Acta Mechanica.K. Austria.G.. “The Role of Laminar-Turbulent Transition in Gas Turbine Engines”. Inc. Ding and D.B. S... Y. Y.. 103 Langtry. R. “A Correlation based Transition Model using Local Variables Part 1. R. 2002. 113. AIAA paper 2005-522.. P. F..B. Kong and R. pp. 1992. Conf. Liu. 18. 112 R. 5. K. “Liquid Jet Atomization and Droplet Breakup Modeling of Non-Evaporating Diesel Fuel Sprays”.1 . 681-687.M. 1811. 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All rights reserved. “Near-Limit Drop Deformation and Secondary Breakup”. S. “Grenzschicht-Theorie”. “Orifice Cavitation and Its Effect on Spray Mixing”. Hsiang and G. on Liquid Atomization and Spray Systems. Reitz. Maier and S. Schmehl. Reitz and R. pp. 287 . USA.D. 107 F. “CFD Analysis of Fuel Atomization. Proc. 970050. 113 Schlichting. Mather and R. Faeth. 1992. 1993. and Gersten.P. Keck. Amsden. Lewis and G. References 121-140 121 T. 117 M. “Modelling of Primary and Secondary Break-Up Processes in High Pressure Diesel Sprays”. All rights reserved. 116 P. 870598. Flame. 35-43.P. 123 B. 7. Majumdar. 122 B. Vol. Iijima and T. 1980. 58. 1987. 118 S. pp. “The TAB Method for Numerical Calculation of Spray Droplet Breakup”. Lettmann and G. 13-22. Baumgarten.O'Rourke and A. Kyoto 2004. 124 Release 12. 1986. Takeno. 120 C. pp. 288 Contains proprietary and confidential information of ANSYS. Vol. Inc. J. 3rd Edition. “Numerical Heat Transfer and Fluid Flow”.1 . 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"A scale-adaptive simulation model for turbulent flow predictions". 128 Kato.© 2009 ANSYS.P. and its subsidiaries and affiliates. 1982. 130 Menter F. and Egorov. Launder. and A. M. AIAA Paper 93-2906. Vol.-Dec.. International Journal of Multiphase Flow.. 132 Menter. 129 Menter. 1998. B. R. I.. and Corradin.. “Burning Velocities of Mixtures of Air with Methanol.E. All rights reserved. AIAA Paper 2003-0767. pp.. F. Kyoto. Reitz. Reno/NV.D. "The modelling of turbulent flow around stationary and vibrating square cylinders". Nouar. Berlin..References 121-140 M. Vol. One hundred years of boundary layer research.. J. NASA TM 108807. 137 Squires. Teubner Verlag. 139 Roache. "Turbulente Strömungen". “Verification and Validation in Computational Science and Engineering”. 140 Casey. References 141-160 141 Ferziger. H. L. "Young-Person's Guide to Detached-Eddy Simulation Grids".. and its subsidiaries and affiliates. J. S. J. 138 Jovic. 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Heat and Fluid Flow.. “Development and Application of SST-SAS Turbulence Model in the DESIDER Project”. 200 Nicoud. No. 1991. “A Dynamic Subgrid-Scale Eddy Viscosity Model”. Turbulence and Combustion.J. 1992. and Kays. Release 12. 633-635. Flow. Vol. 199 Lilly. 4.K.... Y. Moffat. Cabot.© 2009 ANSYS. 282-300. All rights reserved.E. and Menter.. Second Symposium on Hybrid RANS-LES Methods. F. F. pp. “Second-moment closure: present … and future”. pp. pp. Technical Report ANSYS / TR-04-04. Fluids A 4 (3). R.. 197 Egorov. and Menter. 1760-1765. D. 1989.M. Inc. M. CA. 62. Interim Report Stanford University. Contains proprietary and confidential information of ANSYS. W. Int.. Inc. 1975. F.. “ The Turbulent Boundary Layer: An Experimental Study of the Transport of Momentum and Heat with the Effect of Roughness”. M. W. Greece. B. P. Piomelli. “A Proposed Modification of the Germano Subgrid-Scale Closure Method”. Release 12. and its subsidiaries and affiliates. All rights reserved.© 2009 ANSYS. Inc. . Inc.1 . Contains proprietary and confidential information of ANSYS. The maximum number of adaption levels is controlled to prevent over-refinement. When running in batch mode. It is used by the solver to calculate pressure-dependent properties (such as density for compressible flow). the new elements have an adaption level that is one greater than the "parent" element. Additional Variables are typically specified as concentrations. 299 . ASM (Algebraic Slip Model) aspect ratio A mathematical form in which geometry may be represented.1 .Glossary Symbols <CFXROOT> The directory in which CFX is installed. Inc. Each time an element is split into smaller elements. and hydro-static pressure (if a buoyant flow) in the cavitation model. scalar component. The aspect ratio is 1 for a regular tetrahedron. absorption coefficient adaption adaption criteria adaption level adaption step Additional Variable Advancing Front and Inflation (AFI) all domains B backup file An intermediate CFX-Solver Results file that can be manually generated during the course of a solution from the CFX-Solver Manager interface by using the Backup action button. Generally speaking. The AFI mesher consists of a triangular surface/tetrahedral volume mesh generator that uses the advancing front method to discretize first the surface and then the volume into an unstructured (irregular) mesh. A way to run some components of ANSYS CFX without needing to open windows to control the process. Each mesh element has an adaption level. A non-reacting. The default meshing mode in CFX. A measure of how close to a regular tetrahedron any tetrahedron is. known as parametric cubic. The absolute pressure is clipped to be no less than the vapor pressure of the fluid. which combine with the tetrahedra to form a hybrid mesh. Also known as normalized shape ratio. Contains proprietary and confidential information of ANSYS. A property of a medium that measures the amount of thermal radiation absorbed per unit length within the medium. such as smoke in air or dye in water. “all domains” refers to all of the domains in the case excluding the immersed solid. reference pressure. See mesh adaption. Backup files should be generated if you suspect your solution may be diverging and want to retain the intermediate solution from which you can do a restart. and its subsidiaries and affiliates. for example: C:\Program Files\ANSYS Inc\v121\CFX\ A absolute pressure The summation of solver pressure. Used for judging how good a mesh is. but gets smaller the flatter the tetrahedron gets. The criteria that are used to determine where mesh adaption takes place. Inc. All rights reserved. a Viewer is not provided and you cannot enter batch mode Release 12.© 2009 ANSYS. Inflation can be applied to selected surfaces to produce prismatic elements from the triangular surface mesh. Additional Variables are used to model the distribution of passive materials in the flow. You can set adiabatic boundary conditions for heat transfer simulations in ANSYS CFX or in ANSYS FLUENT. This is done for backwards compatibility. One loop of the adapt-solve cycle in the mesh adaption process. In immersed-solids cases in CFD-Post. only the wireframe needs to keep track of both “all domains” and the immersed solid. adiabatic The description of any system in which heat is prevented from crossing the boundary of the system. The degree that a mesh element has been refined during adaption. and initial values. more easily.commands at a command prompt. boundary conditions. solver parameters and any initial values. the name of which is specified when executing the command to start batch mode. and the shell-like representations produced by most CAD systems. See buoyant flow. Inc.1 . The properties of a component are calculated from the mass fractions of the constituent materials and are based on the materials forming an ideal mixture. It is created by CFX and used as input to CFX-Solver. The science of predicting fluid flow.2. the Boussinesq approximation is employed. A collection of surfaces that completely and unambiguously enclose a finite volume. component A substance containing one or more materials in a fixed composition. A file that contains the specification for the whole simulation. surface mesh. and related phenomena by solving the mathematical equations that govern these processes using a numerical algorithm on a computer. Expressions can be developed within CFX using the Expression Editor. CEL can be used to apply user-defined fluid property dependencies.cse). or. A surface or edge that limits the extent of a space. If density is a function of one of these. mechanical movement (as in fan rotation). phase change (as in freezing or boiling)." This term was coined to distinguish between the tri-parametric entities. 300 Contains proprietary and confidential information of ANSYS. A boundary can be internal (the surface of a submerged porous material) or external (the surface of an airfoil). stress or deformation of related solid structures (such as a mast bending in the wind). For fluids where density is not a function of temperature. Command actions are: • • • Statements in session files Commands entered into the Tools > Command Editor dialog box Commands entered in Line Interface mode. pressure. usually related to the input and output of data from the system.© 2009 ANSYS. All rights reserved. if relevant) are calculated. Commands are issued via a CFD-Post session file (*. in front of which no geometry is drawn. Modelers that create so-called B-Rep models create "bodies. boundary boundary condition Boussinesq model buoyant flow C CEL (CFX Expression Language) CFD (Computational Fluid Dynamics) A high level language used within CFX to develop expressions for use in your simulations. compressible flow computational mesh . 307). boundary conditions. or Additional Variables. Flow that is driven wholly or partially by differences in fluid density. including the geometry. Flow in which the fluid volume changes in response to pressure change. then the Full Buoyancy model is employed. Release 12. Compressible flow effects can be taken into consideration when the Mach number (M) approaches approximately 0. fluid properties. These commands force CFD-Post to undertake specific tasks. The session file can be created using a text editor. CFX-Solver Input file CHT (Conjugate Heat Transfer) clipping plane command actions All such actions must be preceded with the > symbol. chemical reaction (as in combustion). Inc. known herein as solids. by recording a session while running in line-interface or GUI mode. This enables you to see parts of the geometry that would normally be hidden. blend factor body A setting that controls the degree of first/second order blending for the advection terms in discrete finite volume equations. See also Power Syntax (p. A collection of points representing the flow field where the equations of fluid motion (and temperature. Heat transfer in a conducting solid. Physical conditions at the edges of a region of interest that you must specify in order to completely describe a simulation. A plane that is defined through the geometry of a model. and its subsidiaries and affiliates. mass transfer (as in perspiration or dissolution). heat transfer. Release 12. which relate the value of a variable in a control volume to the value in neighboring control volumes. this is set to the No Slip Adiabatic Wall boundary condition.1 . on the edges of the geometry) are not precisely equal to the specified boundary conditions when CFX-Solver finishes its calculations. All rights reserved. it can be more helpful if the nodes at the boundary do contain the specified boundary conditions and so "corrected boundary node values" are used. This will ensure the velocity is display as zero on no-slip walls and equal to the specified inlet velocity on the inlet. although you can change the type of default boundary condition in CFX. This determines the modeling of specific features such as heat transfer or buoyancy.control volume conservative values convergence corrected boundary node values The volume surrounding each node. with each domain defined by separate 3D primitives. Inc. for example. See corrected boundary node values. a line is also a curve. the value of velocity on a node on the wall will not be precisely zero. The physical nature of the flow. A state of a solution that occurs when the change in residual values from one iteration to the next are below defined limits. and the value of temperature on an inlet may not be precisely the specified inlet temperature. For visualization purposes. CFX-Solver is an example of a coupled solver. By default. curves are displayed in yellow in ANSYS CFX. The advantages of a coupled solver are that it is faster than a traditional solver and fewer iterations are required to obtain a converged solution. 301 . Detached Eddy Simulation (DES) Direct Numerical Simulation (DNS) discretization domain There can be many domains per model. The equations of fluid flow are solved over each control volume. The equations of fluid flow cannot be solved directly. Normally. The domain requires three specifications: • • • The region defining the flow or conducting solid. Inc. defined by segments of the faces of the elements associated with each node. The properties of the materials in the region. A domain is formed from one or more 3D primitives that constrain the region occupied by the fluid and/or conducting solids. A model that covers the boundary layer by a RANS model and switches to a LES model in detached regions.© 2009 ANSYS. and its subsidiaries and affiliates. curve D default boundary condition The boundary condition that is applied to all surfaces that have no boundary condition explicitly set. coupled solver A solver in which all of the hydrodynamic equations are solved simultaneously as a single system. A CFD simulation in which the Navier-Stokes equations are solved without any turbulence model. Node values obtained by taking the results produced by CFX-Solver (called "conservative values") and overwriting the results on the boundary nodes with the specified boundary conditions. See Also boundary condition. Fluid domains define a region of fluid flow. A general vector valued function of a single parametric variable. The values of some variables on the boundary nodes (that is. Contains proprietary and confidential information of ANSYS. Corrected boundary node values are obtained by taking the results produced by CFX-Solver (called "conservative values") and overwriting the results on the boundary nodes with the specified boundary conditions. Discretization is the process by which the differential equations are converted into a system of algebraic equations. Multidomain problems may be created from a single mesh if it contains multiple 3D primitives or is from multiple meshes. See Also Navier-Stokes equations. In CFX. For instance. while solid domains are regions occupied by conducting solids in which volumetric sources of energy can be specified. Regions of fluid flow and/or heat transfer in CFX are called domains. Also called a symmetry boundary. or several flow regions. A flow field that is located outside of your geometry. and its subsidiaries and affiliates. See Also internal flow. Inc. Flow where the conditions of the flow entering and leaving one half of a geometry are the same as the conditions of the flow entering and leaving the other half of the geometry. It is also known as an implicit surface.dynamic viscosity dynamical time Dynamic viscosity. The program that administers ANSYS licensing. uninterrupted flow region.© 2009 ANSYS. . The surfaces bounding the flow field. A property of an object that describes how much radiation it emits as compared to that of a black body at the same temperature. Inc. Expansion factor is also used to specify the rate of mesh coarsening from a mesh control. Release 12. A boundary face is an element face that exists on the exterior boundary of the domain. edge emissivity expansion factor expression editor Expression Language external flow F face “Face” can have several meanings: • • • • FLEXlm fluid domain flow boundaries flow region A solid face is a surface that exists as part of a solid. each exhibiting different characteristics. All rights reserved. For advection dominated flows. also called absolute viscosity.1 . form-driven facility within CFX for developing expressions. this is an approximate timescale for the flow to move through the Domain. Surfaces composed of edges that are connected to each other. An example of an eddy viscosity model is the k-ε model. An element face is one side of a mesh element. A volumetric space containing a fluid. Adjacent faces share at least one edge. A substance that tends to flow and assumes the shape of its domain. See Also CEL (CFX Expression Language). 302 Contains proprietary and confidential information of ANSYS. See domain. Element edges belonging to only one element. Setting the physical time step (p. The rate of growth of volume elements away from curved surfaces and the rate of growth of surface elements away from curved boundaries. E eddy viscosity model A turbulence model based on the assumption that Reynolds stresses are proportional to mean velocity gradients and that the Reynolds stress contribution can be described by the addition of a turbulent component of viscosity. is a measure of the resistance of a fluid to shearing forces. such as a gas in a duct or a liquid in a container. An interactive. The edge entity describes the topological relationships for a curve. Depending on the flow characteristics. 306) size to this value (or a fraction of it) can promote faster convergence. See CEL (CFX Expression Language). you may have a single. flow symmetry fluid free edges G gas or liquid surface A type of boundary that exhibits no friction and fluid cannot move through it. inactive regions are hidden from view in the graphics window. tetrahedral. IGES files can be imported into CFX. Flow in which the density is constant throughout the domain. on some Windows NT systems.005 in whichever geometry units you are working. read from an existing solution. The volume mesh can contain hexahedral. with six faces and eight vertices. The group's definition includes: • • • • Group name Group status (current/not current) Group display attributes (modified under Display menu) A list of the geometric and mesh entities that are members of the group. inactive region incompressible flow incremental adaption inertial resistance coefficients initial guess initial values Release 12. or given default values. However. The values of dependent variables at the initial time of a transient simulation. The directory on all UNIX systems and some Windows NT systems where each user stores all of their files. the ANSYS CFX setup file cfx5rc can be placed in c:\winnt\profiles\<user>\Application Data\ANSYS CFX\<release>. Contains proprietary and confidential information of ANSYS. where <user> is the user name on the machine. is normally . Mathematical terms used to define porous media resistance. Density and specific heat capacity for general fluids may depend on pressure. temperature. The density is automatically computed using this relationship and a specified molecular weight. All rights reserved. The state of a geometry where each half is a mirror of the other. however. A named collection of geometric and mesh entities that can be posted for display in viewports. Incremental adaption is much faster than re-meshing. I ideal gas IGES (Initial Graphics Exchange Specification) file implicit geometry import mesh A fluid whose properties obey the ideal gas law. the edges of a surface are implicit curves. The values of dependent variables at the start of a steady state simulation. A meshing mode that allows import of volume meshes generated in one of a number of external CFD packages. For example.1 . users do not have an equivalent to the UNIX home directory. or read from an existing solution. An ANSI standard formatted file used to exchange data among most commercial CAD systems. These can set explicitly. prismatic. or a solid region where temperatures are not being calculated. hybrid values See corrected boundary node values. A fluid or porous region where flow and (if relevant) temperatures are not being calculated. and pyramidal element types. See Also ideal gas. The minimum distance between two geometry entities below which CFX considers them to be coincident. the mesh quality is limited by that of the initial mesh. Other files can be put into a directory set by the variable HOME. By default. and its subsidiaries and affiliates. Inc. defined in the template database. In this case.general fluid A fluid whose properties may be generally prescribed in ANSYS CFX or ANSYS FLUENT. 303 . The method of mesh adaption used by CFX where an existing mesh is modified to meet specified criteria. Inc. and where various setup files are stored.© 2009 ANSYS. Geometry that exists as part of some other entity. and any Additional Variables. global model tolerance geometric symmetry group H hexahedral element home directory A mesh element with the same topology as a hexahedron. These can be either set explicitly. The default setting of global model tolerance. interior boundary internal flow interpolation isentropic isosurface Isovolume A locator that consists of a collection of volume elements. for example. The description of a process where there is no heat transfer and entropy is held constant. J JPEG file A common graphics file type that is supported by CFD-Post output options. All rights reserved. by setting the fluid velocity or mass flow rate. A function of the fluid medium that describes how rapidly an Additional Variable would move through the fluid in the absence of convection. These types of boundaries are useful to separate two distinct fluid regions from each other. A flow field is laminar when the velocity distributions at various points downstream of the fluid entrance are consistent with each other and the fluid particles move in a parallel fashion to each other. and one for turbulence dissipation (epsilon). 304 Contains proprietary and confidential information of ANSYS. For example. or to separate a porous region from a fluid region. A surface of constant value for a given variable. such as flow through a pipe. The k-epsilon turbulence model solves two additional transport equations: one for turbulence generation (k). providing the correct syntax is used. A mode in which you type the commands that would otherwise be issued by the GUI.© 2009 ANSYS. 310) based on the concept that turbulence consists of small eddies that are continuously forming and dissipating. See Also external flow. The process of transferring a solution from a results file containing one mesh onto a second file containing a different mesh.inlet boundary condition instancing A boundary condition (p. 300) for which the quantity of fluid flowing into the flow domain is specified. A three-dimensional surface that defines a single magnitude of a flow variable such as temperature. etc. Aside from that difference. all of which take a value of a variable greater than a user-specified value. Flow through the interior of your geometry. K k-epsilon turbulence model A turbulence model (p. Release 12. all commands that work for the Command Editor dialog box will also work in line interface mode. A viewer is provided that shows the geometry and the objects created on the command line. Line interface mode differs from entering commands in the Command Editor dialog box in that line interface action commands are not preceded by a > symbol. The velocity distributions are effectively layers of fluid moving at different velocities relative to each other. The process of copying an object and applying a positional transform to each of the copies.1 . Large Eddy Simulation Model (LES) legend line interface mode The Large Eddy Simulation model decomposes flow variables into large and small scale parts. when you still want flow to occur between the two regions. . Inc. pressure. velocity. a row of turbine blades can be visualized by applying instancing to a single blade. This model solves for large-scale fluctuating motions and uses “sub-grid” scale turbulence models for the small-scale motion. and characterized by low Reynolds Number. See legend. and its subsidiaries and affiliates. key kinematic diffusivity L laminar flow Flow that is dominated by viscous forces in the fluid. A boundary that allows flow to enter and exit. A color key for any colored plot. Inc. A fluid consisting of more than one component. the geometry units. The method you use to create your mesh of nodes and elements required for analysis. the mesh can automatically be refined in locations where solution variables are changed rapidly. Incremental adaption takes an existing mesh and modifies it to meet the adaption criteria. Examples are planes and points. By simultaneously pressing the MAlt key and a mnemonic is an alternative to using the mouse to click on a menu title. and its subsidiaries and affiliates. line. and the Alt key on most keyboards for most Windows-based systems. The properties of a multicomponent fluid are dependent on the proportion of constituent components. Contains proprietary and confidential information of ANSYS. In CFX. 303). It can be created only for transient calculations. The alternative is re-meshing. The process by which. Inc. 299). incremental adaption is used because this is much faster. As the solution is calculated. M MAlt key (Meta key) The MAlt key (or Meta key) is used to keyboard select menu items with the use of mnemonics (the underscored letter in each menu label). A term used in ANSYS FLUENT documentation that is equivalent to the ANSYS CFX term constant streamwise location. multicomponent fluid N Navier-Stokes equations new model preferences node allocation parameter The fundamental equations of fluid flow and heat transfer. if relevant) are calculated. solved by CFX-Solver. though the proportions of each component may vary in space or time. Mesh controls can take the form of a point. The ration of the mass of a fluid component to the total mass of the fluid. The MAlt key is different for different brands of keyboards. 303) mass fraction material meridional mesh mesh adaption A file that contains only the results for selected variables. the "Compose Character" key for Tektronix keyboards. once or more during a run. and no mesh. A substance with specified properties. the mesh is selectively refined at various locations. such as density and viscosity. There are two main meshing modes: • • minimal results file Advancing Front and Inflation (AFI) (p. A parameter that is used in mesh adaption (p. The components are assumed to be mixed at the molecular level. or triangle. however. 305) to determine how many nodes are added to the mesh in each adaption step (p. this imposes the limitation that the resulting mesh quality is limited by the quality of the initial mesh. Preferential settings for your model that define the meshing mode (p. mesh control meshing mode A refinement of the surface and volume mesh in specific regions of the model.© 2009 ANSYS.locator A place or object upon which a plot can be drawn.1 . There are two general methods for performing mesh adaption. and the global model tolerance (p. It is useful when you are only interested in particular variables and want to minimize the size of the results for the transient calculation. 299) import mesh (p. They are partial differential equations. depending on criteria that you can specify. 305 . Inc. All rights reserved. in which the whole geometry is re-meshed at every adaption step according to the adaption criteria. Values for mass fraction range from 0 to 1. Release 12. in order to resolve the features of the flow in these regions. Some examples of MAlt keys include the " " key for Sun Model Type 4 keyboards. 305). A collection of points representing the flow field where the equations of fluid motion (and temperature. Inc. The list processor interprets the contents of all selected data boxes. and its subsidiaries and affiliates. A locator that consists of user-defined points. Four sided surfaces parameterized in two normalized directions. where n is the number of dimensions of the space in which the point resides. P parallel runs parametric equation Separate solutions of sections (partitions) of your CFD model. For ANSYS CFX. The character strings are called "pick lists. A fluid that does not follow a simple linear relationship between shear stress and shear strain. reference pressure. By setting the edge angle to 0. the post-processor is CFD-Post.© 2009 ANSYS. and whether a restart is necessary. non-Newtonian fluid normal normalized shape ratio O open area OpenGL outlet outline plot output file The area in a porous region that is open to flow. A text file produced by CFX-Solver that details the history of a run. the surface mesh can be displayed over the whole geometry. The direction perpendicular to the surface of a mesh element or geometry. and hydro-static pressure (if a buoyant flow). Inc. This pressure. run on more than one processor." Any means of viewing the results in CFD-Post. The time represented in each iteration of the solution. A graphics display system that is used on a number of different types of computer operating systems. A model in ANSYS CFX that takes inter-particle collisions and their effects on the particle and gas phase into consideration. A boundary condition where the fluid is constrained to flow only out of the domain. or you can type or paste in the string directly. Six-sided solids parameterized in three normalized directions. Types of plots include vectors. Parametric surfaces are colored green ANSYS CFX. The positive direction is determined by the cross-product of the local parametric directions in the surface. A boundary condition where the values on the first surface specified are mapped to the second surface. . used by the solver to calculate cavitation sources. The component used to analyze and present the results of the simulation. can be negative or positive. All selected data boxes in CFX expect character strings as input. parametric solids parametric surfaces Particle-Particle Collision Model (LPTM-PPCM) periodic pair boundary condition physical time step pick list plot point point probes polyline post-processor Release 12. and contour plots. or express the coordinates of the points of a surface as functions of two parameters.non-clipped absolute pressure The summation of solver pressure. or express the coordinates of the points of a solid as functions of three parameters. streamlines. It is important to browse the output file when a run is finished to determine whether the run has converged. Points placed at specific locations in a computational domain where data can be analyzed. An ordered n-tuple. Parametric solids are colored blue ANSYS CFX. See aspect ratio. A plot showing the outline of the geometry. 306 Contains proprietary and confidential information of ANSYS. Any set of equations that express the coordinates of the points of a curve as functions of one parameter. The mapping can be done either by a translation or a rotation (if a rotating frame of reference is used). The character strings may be supplied by the graphics system when you select an entity from a viewport.1 . All rights reserved. 307). and custom macros (subroutines). It is consulted when the Parallel Virtual Machine is started to determine where PVM is located on each slave node. X is taken in the local X of that frame. A solution is considered to be converged when the residuals are below a certain value. All rights reserved. 2. but clipped such that the absolute pressure is non-negative.1 . or a porous material. CFX-Solver writes the residuals to the output file (p. In the cavitation model. and 3 will be used to define the X.© 2009 ANSYS. ANSYS FLUENT allows residuals to be plotted during the solution process. It is used for post-processing only. etc. A 3D mesh element shaped like a triangular prism (with six vertices). logic.ccl file by an exclamation mark (!) at the start of each line. For details. 305) are solved iteratively. 307 . For domains. The database file containing information about where ANSYS CFX. It is a simple language that can be used to create objects or perform actions in the post-processor. simple syntax lines may refer to Perl variables and lists. It is particularly appropriate where strong flow curvature. in order to perform a restart. a solid material. and separation are present. Sometimes known as a wedge element. In between Perl lines. Inc. see Power Syntax in ANSYS CFX (p. then the principal axes 1. respectively. The change in the value of certain variables from one iteration to the next. If the coordinate frame is a non-rectangular coordinate frame. The default is CFX global system (Coord 0).Power Syntax The CFX Command Language (CCL) is the internal communication and command language of CFD-Post. and initial values. Power Syntax programming uses the Perl programming language to allow loops. boundary conditions. the pre-processor is CFX-Pre. Lines of Power Syntax are identified in a . swirl. and its subsidiaries and affiliates. When the Navier-Stokes equations (p. pyramid element R reference coordinate frame The coordinate frame in which the principal directions of X or Y or Z are taken. the resulting equations have six stress terms that do not appear in the laminar flow equations. the reference coordinate frame is always treated as Cartesian. pre-processor pressure prism or prismatic element PVM (Parallel Virtual Machine) PVMHosts file The component used to create the input for the solver. Power Syntax enables you to embed Perl commands into CCL to achieve powerful quantitative post-processing. A 3D mesh element that has five vertices. The discretized Navier-Stokes equations (p. region residuals An area comprised of a fluid. and Z directions. and consequently PVM. Reynolds averaged Navier-Stokes (RANS) equations Reynolds stress The stress added to fluid flow due to the random fluctuations in fluid momentum in turbulent flows. A model that solves transport equations for the individual Reynolds stress components. irrespective of coordinate frame type. results file (CFX-Solver Results file) A file produced by CFX-Solver that contains the full definition of the simulation as well as the values of all variables throughout the flow domain and the history of the run including residuals (p. pressure is the same as solver pressure. The environment that controls parallel processes. For ANSYS CFX. Inc. 259). 305) are derived for time averaged turbulent flow to take into account the effect of these fluctuations in velocity. An CFX-Solver Results file can be used as input to CFD-Post or as an input file to CFX-Solver. Reynolds stress turbulence model Release 12. These are known as Reynolds stresses. have been installed on each PVM node. The residual for each equation gives a measure of how far the latest solution is from the solution in the previous iteration. Y. Contains proprietary and confidential information of ANSYS. 306) so that they can be reviewed. Time-averaged equations of fluid motion that are primarily used with turbulent flows. ).© 2009 ANSYS. Inc. For these problems and others. A k − ω based SST model that accounts for the transport of the turbulent shear stress and gives highly accurate predictions of the onset and the amount of flow separation under adverse pressure gradients. It is based on renormalization group analysis of the Navier-Stokes equations. singleton (CCL object) Release 12. but the model constants differ. 308 Contains proprietary and confidential information of ANSYS. a singleton can appear just once as the child of a parent object.ses. The singleton object for a session file is declared like this: SESSION: Session Filename = <filename>. pressure. and its subsidiaries and affiliates. All rights reserved. A variable that has only magnitude and not direction. where steady-state simulations are not of sufficient accuracy and do not properly describe the true nature of the physical phenomena. The transport equations for turbulence generation and dissipation are the same as those for the standard k-epsilon model. Rotating Frame of Reference (RFR) run S Sampling Plane scalar variable Scale Adaptive Simulation (SAS) model A locator that is planar and consists of equally-spaced points. It has the extension . A shear stress transport model used primarily for unsteady CFD simulations. if necessary).1 . However. and produces an output file and a results file (if successful). there may be several instances of a named object of the same type defined with different names. A singleton object that consists of an object type at the start of a line. A material that does not flow when a force or stress is applied to it. followed by a : (colon). The general class of vector valued functions of three parametric variables. The object definition is terminated by the string END on a line by itself. speed (the magnitude of the velocity vector). A process that requires the specification of the CFX-Solver input file (and an initial values file. Examples are temperature. ANSYS CFX and ANSYS FLUENT can solve for fluid flow in a geometry that is rotating around an axis at a fixed angular velocity. the SAS-SST model provides a more accurate solution than URANS models. Cases that may benefit from using the SAS-SST model include: • • Unsteady flow behind a car or in the strong mixing behind blades and baffles inside stirred chemical reactors Unsteady cavitation inside a vortex core (fuel injection system) or a fluid-structure interaction (unsteady forces on bridges. and the constant Cε1 is replaced by the function Cε1RNG.cse END The difference between a singleton object and a named object is that after the data has been processed. 304). and which consists of all the points that intersect the plane and the mesh edges. other models use two equations for the two main turbulent scales. Inc.Reynolds stress models in general tend to be less numerically robust than eddy viscosity models such as the k-epsilon turbulence model (p. A file that contains the records of all the actions in each interactive CFX session. Subsequent lines may define parameters and child objects associated with this object. etc. where steady-state simulations are not of sufficient accuracy and do not properly describe the true nature of the physical phenomena. slice plane solid A locator that is planar. 304). wings. and any component of a vector quantity. A coordinate system that rotates. Second Moment Closure models session file (CFX) Shear Stress Transport (SST) Models that use seven transport equations for the independent Reynolds stresses and one length (or related) scale. RNG k-epsilon turbulence model An alternative to the standard k-epsilon turbulence model (p. . A locator that consists of a collection of volume elements that are contained in or intersect a user-defined sphere. 309 . Contains proprietary and confidential information of ANSYS. tubes. it can be negative or positive. β. The velocity at which small amplitude pressure waves propagate through a fluid. theta is increasing in the clockwise direction.solid sub-domain solver solver pressure spanwise coordinate specific heat specific heat capacity speed of sound sphere volume state files A region of the fluid domain that is occupied by a conducting solid. that allow the prescription of momentum and energy sources. Note that. thermal expansivity theta The property of a fluid that describes how a fluid expands as the result of an increase in temperature. They differ from session files in that only a snapshot of the current state is saved to a file. The movement of a fluid at a speed less than the speed of sound. A simulation that is carried out to determine the flow after it has settled to a steady state. and its subsidiaries and affiliates. neutrally-buoyant particle would take through the flow domain.1 . Stream plots can be shown as lines. producing the required results. They can be used to model regions of flow resistance and heat source. The amount of heat energy required to raise the temperature of a fixed mass of a fluid by 1K at constant pressure. 300). Defined as 0°C (273. ANSYS CFX can model heat transfer in such a solid. within the region of bounding solids for a fluid domain.013x105 Pa).out file it is called Pressure. The ratio of the amount of heat energy supplied to a substance to its corresponding change in temperature. or ribbons. timestep Release 12. assuming the displayed solution to be steady state. You can also write your own state files using any text editor. Inc. The component that solves the CFD problem. Files produced by CFD-Post that contain CCL commands. A plot that colors a surface according to the values of a variable. In the . you can choose to display contours. or use as a template to create a fluid with your own properties. The path that a small. Velocity parallel to the boundary is also symmetric and velocity normal to the boundary is zero. A term used in ANSYS FLUENT documentation that is equivalent to the ANSYS CFX term constant span. When looking along the positive direction of the axis of rotation. this is known as CHT (Conjugate Heat Transfer) (p. Regions comprising a solid or set of solids. All rights reserved. Note that the theta coordinate in CFD-Post does not increase over 360°.© 2009 ANSYS. Also known as the coefficient of thermal expansion.15K) and 1 atm (1. The property of a fluid that characterizes its ability to transfer heat by conduction. A plot that shows the streamlines of a flow. A boundary condition where all variables except velocity are mathematically symmetric and there can be no diffusion or flow across the boundary. Inc. even with time constant boundary conditions. The pressure calculated by solving conservative equations. even for spiral geometries that wrap to more than 360°. A property of a substance that indicates its ability to transfer thermal energy between adjacent portions of the substance. some flows do not have a steady-state solution. The angular coordinate measured about the axis of rotation following the right-hand rule. See physical time step. Additionally. STP (Standard Temperature and Pressure) steady-state simulation stream plot streamline subdomains subsonic flow surface plot symmetry-plane boundary condition T template fluid thermal conductivity One of a list of standard fluids with predefined properties that you can use 'as is'. measured data. In turbulent flow. the size of the arrows may show the magnitude of the velocity of the flow at that point. turbulent flow V variable A quantity such as temperature or velocity for which results have been calculated in a CFD calculation.05%. Inc. All rights reserved. This produces an irregular mesh. 310 Contains proprietary and confidential information of ANSYS. you will have a good estimate of the turbulence intensity at the inlet boundary from external. Inc.1 . Optionally. since the turbulent eddies cannot be larger than the duct. turbulence model A model that predicts turbulent flow (p. the turbulence intensity at the inlets is totally dependent on the upstream history of the flow. the turbulence intensity may be as high as a few percent. The ratio of the root-mean-square of the velocity fluctuations to the mean flow velocity. the free-stream turbulence intensity may be as low as 0. The available turbulence models in ANSYS CFX are: • • • • k-epsilon turbulence model (p. For example. such as a perforated plate. A turbulence intensity of 1% or less is generally considered low and turbulence intensities greater than 10% are considered high. For internal flows. Flow that is randomly unsteady over time. An approximate relationship can be made between the turbulence length scale and the physical size of the duct that. it is more appropriate to base the turbulence length scale on the characteristic length of the obstacle rather than on the duct size. edge. The shape. 312) Turbulence models allow a steady state representation of (inherently unsteady) turbulent flow to be obtained. in time. If the turbulence derives its characteristic length from an obstacle in the flow. Used in viewing CFD results in order to visualize the mechanics of the fluid flow. 307) zero equation turbulence model (p. turbulent A flow field that is irregular and chaotic look. In modern low-turbulence wind tunnels. 310). the turbulence length scale is restricted by the size of the duct. while not ideal. and its subsidiaries and affiliates. Portions of a mesh that are the result of meshing geometry with two opposing edges that have different mesh seeds. vector plot A plot that shows the direction of the flow at points in space. If the flow upstream is under-developed and undisturbed. turbulence length scale A physical quantity related to the size of the large eddies that contain the energy in turbulent flows. 304) RNG k-epsilon turbulence model (p. 308) Reynolds stress turbulence model (p. you can use a low turbulence intensity. Release 12. verification . direction. Particles that follow a flow pathline. can be applied to most situations. node. A characteristic of turbulent flow is chaotic fluctuations in the local velocity. The vectors may also be colored according to the value of any variable. a fluid particle's velocity changes dramatically at any given point in the flow field. using arrows. If the flow is fully developed. 299). and face numbering of an element. making computational analysis of the flow more challenging. In fully-developed duct flows. if you are simulating a wind-tunnel experiment. the turbulence intensity in the free stream is usually available from the tunnel characteristics.tolerance topology tracers transitions turbulence intensity See global model tolerance. See also Additional Variable (p. and magnitude.© 2009 ANSYS. Ideally. A check of the model for validity and correctness. Comment Viewer. which you access from tabs at the bottom of the area. viewport (CFX) There are the following types of CFX viewports: current viewport The viewport currently being displayed. viscosity viscous resistance coefficients Volume of Fluid (VOF) method The ratio of the tangential frictional force per unit area to the velocity gradient perpendicular to the flow direction. The viewport's definition includes: • • • • • • • The viewport name The status of the viewport (posted or unposted. Variables. and its subsidiaries and affiliates. Table Viewer. The area of CFX-Pre and CFD-Post that contains the Outline. Expressions. and Turbo workspaces. posted viewport A viewport that has been selected for display. A term to define porous media resistance.© 2009 ANSYS. which you access from the tabs at the top of the area. An assigned. 311 . and analysis results.1 . See also CFD-Post Graphical Interface (p. target viewport A viewport selected for a viewport modify action. Release 12. 11). and Report Viewer. Preference. current or not current) Viewport display attributes A definition of the current view A current group A list of the posted groups for display A graphics environment accessed from Display. Calculators. A technique for tracking a fluid-fluid interface as it changes its topology. Inc. Contains proprietary and confidential information of ANSYS. Y y+ (YPLUS) A non-dimensional parameter used to determine a specific distance from a wall through the boundary layer to the center of the element at a wall boundary. Inc. stored in the CFX database.viewer area The area of ANSYS CFX that contains the 3D Viewer. All rights reserved. See prism or prismatic element. finite elements. The following actions can be performed only on the current viewport: • • Changing the view by using the View menu or mouse. W wall wedge element workspace area A generic term describing a stationary boundary through which flow cannot pass. Posting titles and annotations by using the Display menu. Any viewport (including the current viewport) can be selected as the target viewport. named. and Group menus that is common to all viewports. Chart Viewer. Each workspace has a tree view at the top and an editor at the bottom (which is often called the Details view). that can be used to display selected portions of a model's geometry. graphics window definition. All rights reserved. Inc. robust solutions for use as initial fields for simulations using more sophisticated turbulence models. and its subsidiaries and affiliates. This model is useful for obtaining quick.Z zero equation turbulence model A simple model that accounts for turbulence by using an algebraic equation to calculate turbulence viscosity. Release 12. Inc. 312 Contains proprietary and confidential information of ANSYS.1 . .© 2009 ANSYS.