Innovation Intelligence

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1 Innovation Intelligence Efficient CFD Meshing Workflow HyperMesh: Geometry Cleanup & Surface Meshing AcuConsole: Volume Meshing & Analysis Setup Rishi Patil, Product Specialist CFD Alexander Gnech, Application Engineer

2 Recapitulation: HyperWorks for CFD Analysis CFD Pre-Processing HyperMesh Work Flow Benefits: Solver Neutral Preprocessor Dedicated CFD User profile Full CAD clean-up capabilities Interactive CFD meshing Morphing Parametrization of FE-models Native I/O Support Acusolve, AFLR3, CFD++, CFX, Fluent, StarCD, CGNS format, OpenFoam,

3 Recapitulation: HyperWorks for CFD Analysis CFD Pre-Processing AcuConsole Workflow Benefits: CAD associativity Full CAE automation capabilities through Python Automatic mesh generation with many advanced features Access to AcuSolve settings (e.g. boundary conditions, solution strategy) Easily handles large models with hundreds of millions of elements

4 Efficient CFD Meshing Workflow - Overview 1. HyperMesh: Import, Cleanup, Modify Geometry Create Closed Surface Mesh Perform Surface Mesh Checks Export via Nastran(Fluent) Format 2. AcuConsole Import Surface Mesh Set Mesh Settings for Volume Meshing (Surface Mesh is maintained by default) Specify Boundary Conditions, Solver Settings Solve Probably best benefit from both products at the moment

5 HyperMesh : Geometry Import Geometry: Connect Solid Geometry: Often, adjacent solids are not connected: e.g. Geometry -> Edit -> Solids -> Boolean Delete Solids and keep bounding surfaces: Clean up CAD geometry to generate water tight model (e.g. edge edit, surface edit panels): Organize surfaces in components (inlet, outlet, walls, etc.):

6 HyperMesh : Surface Meshing Generate closed Surface Mesh ONLY ( ) with appropriate element size to represent geometry (this surface mesh will be used as starting point: discrete geometry by AcuConsole for volume meshing)

7 HyperMesh: Checks Before exporting this surface mesh it is important to do perform some checks. Free edges: T-Connections: They may exist in a geometry if there are three surfaces coming in contact at one edge. Check if T-Connections are desired in geometry or they are introduced due to incorrect meshing.

8 HyperMesh: Checks Duplicate elements & Connectivity: Intersections and Penetrations (including self interference):

9 HyperMesh : Scaling Scale components appropriately, so that dimensions represent geometry/mesh in meters. It is advisable to have geometry in meters before importing into AcuConsole. HyperMesh is unit less. However, geometry imported from CAD would be typically in millimeters and AcuConsole assumes imported surface mesh is meters. In this case components are scaled down (Scale -) by factor of 1000.

10 HyperMesh : Export Export this surface mesh using Nastran (Fluent) solver format to create.nas file

11 AcuConsole: Import Surface Mesh Import Nastran surface mesh (.NAS) file and check if following options are used: - Volume grouping option = By volume regions - Surface grouping option = By attributes - Surface attribute string = HMNAME COMP - Separate internal faces: - Off: One surface set for an interface between two volumes is created - On: Two surface sets for an interface between two volumes are created, each belonging to one volume. Necessary e.g. for CHT between Fluid & Solid

12 AcuConsole : Recheck Dimensions Imported surface mesh retains component (surface) names assigned in HyperMesh: Check with Surface -> Info, if imported surfaces have appropriate dimension. e.g. here inlet has a diameter of m

13 AcuConsole : Volume Meshing AcuConsole can be used to create volume mesh from the imported surface mesh, using normal AcuConsole procedure. (Global Mesh Attribute, Surface Mesh Attribute, Boundary Layer Parameters, etc.) While generating volume mesh, original surface mesh from HyperMesh may be retained or overwritten by using the option : Modify the original surface mesh