Strategies for CFD/Fluids Meshing in Ansys Workbench

Ansys Workbench offers various strategies for CFD/Fluids meshing. For each strategy, certain defaults are in place to target the particular needs of an analysis. The strategies and circumstances in which each of them are appropriate are described below. In all cases, your first decision is to determine whether you want to use assembly meshing or part-based meshing.

Tetra Dominant Meshing - Patch Conforming Tetra/Prism Meshing

The first strategy is to use conformal tetra/prism meshing plus the default Sweep method. This strategy is recommended for models involving moderately clean CAD (for example, native CAD, Parasolid, ACIS, and so on) for which you desire a tetra/hybrid dominant mesh.

Although the Patch Conforming Tetra mesh method is fully automated, it interacts with additional mesh controls and capabilities as necessary, including:

  • Advanced tetra and inflation layer technology

  • Pinch controls for removing small features at the mesh level (offered as an alternative to Virtual Topologies, which work at the geometry level)

  • Sizing controls for providing greater control over mesh distribution

  • Conformal swept regions

  • Body of influence (BOI) for setting one body as a size source for another body

Tetra Dominant Meshing - Patch Independent Tetra/Prism Meshing

An alternative for those desiring a tetra dominant mesh is Patch Independent Tetra/Prism meshing. This approach is best for "dirty CAD"—CAD models with many surface patches (for example, IGES, CATIA V4, and so on) and in cases with large numbers of slivers/small edges/sharp corners. It includes support for post inflation, as well as CAD simplification built-in to the tetra mesher.

Note:  The Patch Independent Tetrahedrons method is being deprecated and will be removed in future releases.

Mapped Hex Meshing - All Hex Swept Meshing

This mapped hex approach (which includes both general Sweep and thin Sweep) is recommended for clean CAD. It supports single source to single target volumes, and may require you to perform manual geometry decomposition.

Benefits of this approach include:

Mapped and Free Meshing - MultiZone Meshing

Best for moderately clean CAD, the MultiZone strategy for meshing provides multi-level sweep with automatic decomposition of geometry into mapped (structured) and free (unstructured) regions. When defining the MultiZone mesh method, you can specify a Mapped Mesh Type and a Free Mesh Type that will be used to fill structured and unstructured regions respectively. Depending on your settings and specific model, the mesh may contain a mixture of hex/prism/tetra elements.

The MultiZone mesh method and the Sweep mesh method described above operate similarly. However, MultiZone has capabilities that make it more suitable for a class of problems for which the Sweep method would not work without extensive geometry decomposition.

Additional benefits of this approach include:

  • Support for 3D inflation

  • Ability to selectively ignore small features