Release_Notes_Actran_14.pdf

March 28, 2018 | Author: sharon | Category: Fluid Dynamics, Parallel Computing, Computational Fluid Dynamics, Mechanics, Physics


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Major new features of Release 14.0 Adaptive Perfectly Matched Layer (APML) This new release integrates a natural extension of the Perfectly Matched Layer (PML) component, the Adaptive PML. The APML component relies on the surface supporting the NRBC. The discretized domain supporting the Perfectly Matched Layer is automatically generated from this one. This allows avoiding the natural limitation of a single PML domain for large frequency domains, as several discretized domain adapted for each frequency band can be generated easily. As a consequence, it is even more attractive from a computational point of view than PML’s for multiple frequency computations. Enhanced Fan Noise excitations The fan noise excitations supported by the LIGHTHILL_SURFACE and MOHRING_SURFACE are enhanced by the support of different additional CFD inputs. The three additional inputs are all expressed in the rotating reference frame, and are transformed within the acoustic static reference frame through the specification of a COUPLING_LINE and ROTATION_SPEED attached to the surface boundary condition. The additional supported inputs are: - - - Multiple Reference Frame (MRF): This simulation technique considers that the flow inside the rotating part is steady in the rotating reference frame,and is thus obtained by means of a steady computation of the Navier- Stokes equations (RANS) translated into the rotating coordinate system. The interface between the rotor-stator interactions is thus approximated. The obtained results are only available at the blade passing frequency and its harmonics. Non-Linear Harmonics - Harmonic Balance method (NLH): This method assumes that the rotor solution could be decomposed into a set of Fourier modes. The frequency associated to these modes are related to Tyler and Sofrin rules and left to user decision. The interface between the rotor-stator interactions is approximated. The obtained results are only available at the blade passing frequency and its harmonics. Sliding mesh with extraction of data inside the rotating frame: This method is very similar to the previous available implementation as we still use unsteady Navierstokes equations solution, but in the rotating reference frame rather than in the stator frame. The main advantage of this method lies in the ability to extract the sources directly in the rotor frame. The obtained results are available at all frequencies. Free Field Technologies SA Actran Release 14.0 These elements are interpolation elements used to distribute mass and loads. the Corcos. aircrafts or cars). These also allow the specification of ponderations between the different independent nodes. spatial. Extended Turbulent Boundary Layers models The current revision of Actran contains additional semi-empirical turbulent boundary layer models to specify the frequency spectrum or the spatial correlation function. besides the already available Goody and user spectra.Advanced Micro-Models for porous materials The current revision of Actran provides additional micro-models extensions for improving the accuracy of modeling porous materials with non-uniform sections and constrictions. and are similar to RBE3 elements of Nastran. This extension is simply activated by specifying the MEAN_VELOCITY within the corresponding VISCOTHERMAL component. The Johnson-Champoux-Allard-Lafarge micro-model can be activated by specifying the thermal permeability while the Johnson-Champoux-Allard-Pride-Lafarge model is selected by adding the specification of viscous and thermal tortuosity. Cockburn and Robertson. Free Field Technologies SA Actran Release 14. Smolyakov and Tkachenko and Modified Chase have been implemented.0 . As most of these models are dedicated to particular applications (submarine. These new elements are supported by the MEAN_CONSTRAIN component. The spatial correlation models of Chase and Efimtsov have also been integrated beside the existing Corcos model. which allows taking into account convection effects in restrained channels. which can be used for particular structural connections such as welding points of glue. the range of supported applications is enlarged. Efimtsov. Maestrella. Smolyakov. It allows a better representation for areas where the flow is important such as restrained channels present in catalytic converters for instance. Convected Visco-thermal acoustic elements The current release of Actran provides an extension to the visco-thermal implementation. Mean Constrain elements This new revision includes support for mean constrain elements. For the frequency spectrum. This includes the support of spherical sources in density formulation within an acoustic component. Impervious boundary condition The handling of pervious or impervious conditions between 2 congruent acoustic components has been made explicit in the current revision of Actran.0 . and are similar to CONM2 elements of Nastran. which can be coupled with static or other rotating components. These new elements are supported by the POINT_MASS component. These allow modeling the acoustic transmission through complex rotating parts. Rotating Acoustic components The current release of Actran includes support for rotating acoustic components. while they do in the current revision. Updated Spring elements The implementation of springs has been improved in the current revision of Actran. Such point masses allow representing lumped structural parts such as seats. while the coupling with static or other rotating components is insured through a ROTATION_INTERFACE data block. these did not accounted for flow in previous revisions. including inertia and offset effects. Convected sources The formulation of acoustic sources in presence of flow has been updated and improved in the current revision of Actran. When present within infinite elements for instance. but also the support of planar and spherical sources in incident/scattered formulation. When using the Free Field Technologies SA Actran Release 14. which has been corrected. insuring rigid body modes by accounting offset between grids. These represent concentrated masses at a particular geometric point.Point Mass elements This new revision includes support for point mass elements. This new implementation is activated by specifying the ALLOW_RIGID_BODY keyword within a DISCRETE component. Discrete elements have been updated to represent a generalized spring element. The specification of the rotation assigned to the acoustic component is supported by the ROTATION_SPEED data block. taking into account their center of gravity and induces inertias. tires. CBEAM. the master process can be suppressed from the factorization to avoid excessive memory consumption on the master process. Free Field Technologies SA Actran Release 14. This type of parallelism allows running hybrid modal-physical computations in parallel.0 . These new load can be specified using the FIELD_POINT_LOAD data block. Field Point Loads The current revision of Actran allows specifying local forces on an arbitrary location. In addition. Ffowcs Williams Hawkings improvements Different additional features are included in the current revision of the FWH utility: - The power radiated through the FWH surface can be evaluated. This behavior was implicitly performed in previous revisions of Actran by assigning a VELOCITY boundary condition between the 2 acoustic components. the local duplication of pressure is now correctly insured. Multiple and single point constraints forces can be accessed. This type of parallelism avoids distributing the assembly and postprocessing of the computation while solving the computation in parallel using the MUMPS solver. This enables to charge existing structures without requiring any additional meshing operations to support the local force. The specification of output requests for particular elements is facilitated through the usage of the STORAGE_ELEMENT data block. CBUSH and CELAS elements. Centralized matrix parallelism The current revision of Actran allows running a computation using a centralized matrix parallelism. Access to elementary indicators in modal coordinates The computation of elementary indicators for modal components has been simplified and enlarged. - Element forces can be computed from CBAR. Element stresses and strains can be computed for 1d elements.IMPERVIOUS boundary condition between 2 acoustic components. and propagated up to the infinite domain. the air gap layer present on top of the different trims is not mandatory anymore. allowing analyzing large time domain data.- Multiplication factors on mirror contributions can be handled using the FWH_SYMMETRY_FACTOR keyword. Actran for Nastran performance improvements The current release of Actran includes a major performance improvement for Actran for Nastran computations. Free Field Technologies SA Actran Release 14. multiple DFTs can now be computed on multiple time domains. In addition. This boundary condition is modeled using the HEAT_RELEASE_RATE data block. Support of OpenFOAM files for ICFD The current revision of iCFD allows using OpenFOAM native files for mean flow interpolation and aero-acoustic sources computations. Finally. This allows investigating the spectral content of the different regions of interest without encountering truncated sources on the borders of the regions. Combustion excitations The current revision of Actran allows modeling combustion excitation by specifying the heat release rate distributed over a particular domain. Evaluation of the pressure on a field mesh is enabled. Multiple source filtering can be specified in separated multiple loads. regions of experimental or numerical data. which drastically decreases the computational time. The size of the reduced impedances of the trims can additionally be decreased by reducing only the normal displacement towards the structural component if a sliding coupling is selected. The computation of the trim impedance can now be performed using the MUMPS solver. Enhanced multiple load capabilities for CAA The current revision of Actran and iCFD allow easing the multiple load capabilities for aero-acoustic computations.0 . which allows to reduce the global size of the trim models. the sliding condition which imposes a normal displacement continuity between the trim and structure. More details on the Nastran PEM feature can be found in the Nastran User’s guide. The value of a constrained mode within MODAL_BASIS component can be made frequency-dependent using a TABLE A RAYLEIGH_SURFACE component can now be included within a STAGGERED_SOLVER. The current revision of iCFD supports star-CCM+ up to version 8. The entire library of material and components present within Actran.02. where it acts as a post-processing component. o Update of property translation for CONM2. o Correct translation of I12 entries for PBAR cards. Different small improvements have been brought to the Nas2Act utility: o Support of spaces within SPC1 cards. The azimuthal revolution has been unified between Actran and Actran DGM.Actran for Nastran Extended physics and coupling methods The physical components present within trim components and available coupling methods with the structure and cavity for trimmed body analysis have been extended in the current revision of Actran. o Update of material properties translation for MAT2 and MAT8 cards. including thin shells. o Support of XYPUNCH requests. RBE3 and CBUSH cards into more adapted Actran equivalent properties. Velocity quantities can now be provided as scalars from Ensight files. Three new coupling methods for coupling the trim component to the cavity and structure have been integrated. Free Field Technologies SA Actran Release 14. which considers the trim as being made of closed pores on its surface. APML and PML components by setting the POWER_EVALUATION to -1. Nastran PEM The Actran for Nastran technology is available directly within MSC Nastran. rigid body elements. o Support of offset arguments for PCOMP cards. Block names of CDB mesh format are now interpreted. the air gap condition for coupling the trim to the structure with a virtual air gap layer and the impervious coupling between the trim and the cavity. Various other improvements - Local quantities can be retrieved within their local coordinate system if specified within the corresponding LOCAL_SYSTEM data block. beams or lumped porous elements among others are now available for the description of the analyzed trim component.0 . The evaluation of quadratic indicators can be de-activated for ACOUSTIC. Free Field Technologies SA Actran Release 14. This allows the usage of planar and spherical sources in far field. Advanced picking operations in ActranVI The current revision of ActranVI allows hiding or showing part of the mesh present within a render window.0 . in order to evaluate the acoustic radiation of these vibrations. This feature accepts transient or frequential data. Incident sources in ActranDGM The current release of ActranDGM allows attaching sources to the exterior domain (outside the BUFFER component). which allows applying a structural result as an acoustic boundary condition. providing connectivity or topological information for the selected entities. The effects of convection and semi-infinite fields can also be accounted for. density or velocity can be applied on this boundary condition. Unified Graphical User Interface All Actran graphical interfaces. It also provides a single console for all applications. In addition.and post-processing operations within a single session file. PLTViewer. Enhanced Thompson boundary condition in ActranDGM The current revision of ActranDGM includes an enhanced Thompson boundary condition.BC_MESH boundary condition in ActranDGM The current revision of ActranDGM integrates the BC_MESH capability. This eases the visual comfort when investigating interior complex parts or results. Any combination of pressure. The integration of this capability within ActranDGM allows performing acoustic radiations of structures up to very high frequencies or on important models sizes. nodes or elements can be easily retrieved directly within the render window. WATERFALLViewer can be accessed within a single frame. which allows to compare different results in the different environments in a single frame. ActranVI. which can be used to simulate an excitation from a neighboring acoustic component to take into account installation effects for instance. which allows performing pre. Free Field Technologies SA Actran Release 14. the assembly time of infinite elements and pentahedral elements has been decreased.0 . Reduced disk access concurrence in parallel computations For out of core computations involving many RHS and processors. Improved assembling time The overall assembly time of Actran computations has been reduced in the current release. different improvements have been integrated. The backtransformation time required for multiple RHS computations has been drastically reduced. This criterion is used to compare the shape of the provided structural modes.0 Reduced memory consumption for modal-physical hybrid analyses The memory consumption of modal-physical hybrid models has been drastically reduced in the current revision of Actran.Modal Assurance Criterion Indicator (MAC) The current release of ActranVI provides a graphical utility to compute the Modal Assurance Criterion between different modal databases. In the current revision. these interfaces are now correctly handled. spurious sources were generated at these locations. Major bug fixes of Release 14. provided from experimental or numerical data. Specifically. Presence of interfaces in CFD files When computing Lighthill sources at interfaces between CFD domains. has been reduced in parallel computations. This was the case for Fluent and OpenFOAM CFD formats. while the disk access concurrence. which is sometimes a bottleneck during the back-transformation phase of an analysis. The azimuthal merging of PLT output files without any MODE is now supported. negative azimuthal orders are now supported for axisymmetric computations. In ActranDGM.0 The computation of Lighthill sources inside a Water environment has been corrected.Multiple Load computations in Actran DGM When running a multiple load computation inside ActranDGM. The usage of a LOCAL_SYSTEM for 2D computations has been corrected. In the current revision.0 . Free Field Technologies SA Actran Release 14. TABLEs are now supported for the Lame entries of an ISENTROPIC_SOLID material. In ActranDGM. each loadcase stops its computational work when reaching its own convergence. DOMAIN supporting a component can now be referenced within a STORAGE_NODE. multiple NON_REFLECTING data blocks caused different issues at handling the damping in buffer regions. Known issues resolved in Release 14. As the different loads are not strictly converging at the same time step. This is corrected in the current revision. this behavior was thus more time consuming than running manually the different loads. it was required that all loads should converge to a steady state in order to stop the computation. Correct support of FIELD for porous material properties. the automatic evaluation of material and velocity properties for the FWH utility correctly accounts for the OPEN_FWH option. The modal acoustic radiation impedance evaluation in ACTRAN_MODAL is now supported in parallel computations. In ActranDGM. The usage of the Skin name for a DOMAIN data block caused the de-activation of this domain.
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