Meshing Techniques in Ansys ICEM CFD 5.0

1. Meshing Techniques in Ansys ICEM CFD 5.0 Christian Nienhüser ANSYS Germany Christian.Nienhueser@ansys.com

2. Contents • New Graphic User Interface • Geometry import, clean up • Meshing Tools • Surface meshing • Patch based • Patch independent • Volume meshing • Tetrahedral • Hexahedral • Hybrid • Outlook • Final remarks CADFEM CZ User’s Meeting

3. Direct CAD CATIA, Pro/E, I-DEAS, UG, SE, SW… Faceted Data STL, Nastran, Patran, VRML… 3rd Party CAD IGES, ACIS, Parasolid… • Create/Edit geometry • Generate mesh • Edit Mesh • Apply Poperties, B.C.’s ICEM CFD Complete CAE Pre-processing Export to Analysis Over 100 supported solver formats. What is ANSYS ICEM CFD? CADFEM CZ User’s Meeting

4. AI*Environment 1.0 ICEM CFD 4.CFX AI*Environment 2.0 AI*Environment / ICEM CFD 5.0 Development Process ICEM CFD 4.2 ICEM CFD 4.3 Classic GUI Classic GUI ICEM CFD / AI*Environment 5.1 CADFEM CZ User’s Meeting

5. New Graphic User Interface • User interface completely redesigned • Integrates Med, Tetra, Prism, Hexa and Visual3 • Layout is • Clean • Modern • Intuitive CADFEM CZ User’s Meeting

6. New Graphic User Interface • Tabbed menus which follow the process • Logical function groups • Model tree • For display control • Right-click to access related options and operations CADFEM CZ User’s Meeting

7. New Graphic User Interface Selection and database management • Selection manager • Selection filters • Part selection by entity • Blanking of specific entities • Improved subsets for geometry/mesh • Easier methods of limiting data displayed CADFEM CZ User’s Meeting

8. New Graphic User Interface • Advanced help browser • Quick-help CADFEM CZ User’s Meeting

9. Direct CAD CATIA, Pro/E, I-DEAS, UG, SolidWorks … Faceted Data STL, NASTRAN, Patran, VRML… Generic CAD IGES, ACIS, DWG, STEP … Unigraphics CATIA SolidWorks Geometry Import ANSYS ICEM CFD STL CADFEM CZ User’s Meeting

10. Geometry Import Hexa for CATIA V5 CADFEM CZ User’s Meeting

11. Model Diagnosis and Repair Build topology function • Tolerance is set automatically on import • Curves are extracted from surface model • Enables model diagnosis • Curves form basis for geometry repair Imported CAD CADFEM CZ User’s Meeting

12. Geometry tools • Repair • Topology checker to find problems in surface data • Surface closing • Surface retrimming/matching • Surface extension • Unsplit surface • Split by curvature • Modify surface normals • Bolt hole detection • Button detection • Fillet detection • Body definitions • From connectivity • Point inside solid • Point creation • From screen • Explicit • Offset • Centerpoint • Between points • Endpoint • Intersection • Along curve • Projection to curve/surface • Surface editing • Surface from curves • Driven surface • Swept surface • Revolved surface • Offset surface • Midsurface • Adjust thickness • Lofted surface • Curtain surface • Surface trimming • Merged surface • Shrink wrapped surface • Standard surfaces • Faceted Surface tools • Curve creation • From points • Arc/Circle • Surface param • Intersection • Surface projection • Concatenation • Segmentation • Surface Boundary • Faceted curve tools CADFEM CZ User’s Meeting

13. STL to B-Spline conversion • Use geometry repair • Convert multiblock mesh to b-spline • Reverse engineering and legacy data support Circle fom points CADFEM CZ User’s Meeting

14. Quad surface meshing patch dependent • All-quadrilateral mesh • CAD geometry • Edge model CADFEM CZ User’s Meeting

15. Quad Surface Meshing Auto-structured meshing • Mapping = 0 • Mapping = 0.2 CADFEM CZ User’s Meeting

16. Extensions • Arbitrary boundary • Holes, prescribed curves and prescribed points • One/some transition triangles • Auto-structured • Mesh refinement CADFEM CZ User’s Meeting

17. Surface meshing enhancements • Unstructured quad meshing algorithm integrated into Hexa mesher. • Allows the easy creation of hybrid structured/unstructured meshes. • Ideal mesh for crash and NVH. • Initial auto blocking from CAD surfaces. • Automatic merging of regions to create a better blocking. • Geometry feature recognition in meshing. CADFEM CZ User’s Meeting

18. Tetra meshing (Octree) • Initial mesh of “Maximum size” elements fills a bounding box CADFEM CZ User’s Meeting

19. Tetra meshing (Octree) • Mesh is subdivided to meet specified sizes • Nodes adjusted to conform to geometry CADFEM CZ User’s Meeting

20. Tetra meshing (Octree) • “Flood fill” process finds volume boundaries CADFEM CZ User’s Meeting

21. Surfaces near stamped label Mesh “walks over” the detail Tetra meshing (Octree) Patch Independence • Mesh “walks over” gaps, overlaps, holes, details • A perfect CAD model is not required • Greatly reduces the amount of required CAD cleanup CADFEM CZ User’s Meeting

22. Tetra meshing (Octree) • Improved: ‘bounding box’ by ‘geometry blow-up’ CADFEM CZ User’s Meeting

23. Tetra meshing: Improved Auto-Volume Detection • Material points are automatically created • Multiple volumes are supported CADFEM CZ User’s Meeting

24. Tetra meshing: Part-by-Part • Enables assemblies to be meshed in batch as component parts • Mesh is non-conformal CADFEM CZ User’s Meeting

25. Tetra meshing: Improved Volume Mesh Controls • Point, line, and volume density • Width parameter extends effect • Volume defined by points or by bounding box around selected entities Point density CADFEM CZ User’s Meeting

26. Hybrid meshes • Tet to hex converter CADFEM CZ User’s Meeting

27. Prism meshing • Prism layers in pure tetra meshes CADFEM CZ User’s Meeting

28. Prism meshing • Prism layers in hybrid meshes • Extrusion of mixed quad/triangle meshes. CADFEM CZ User’s Meeting

29. Hybrid meshing • New hexahedral-dominant meshing CADFEM CZ User’s Meeting

30. Volume tetra -> add prisms -> convert interior to hexas. Surface tri/quad mesh -> add prisms -> fill with tets. Surface quad mesh -> add boundary hexas -> fill with hexas/tetras/pyramids/prisms Hybrid meshing (outside of Hexa) Easily in any order/any element type CADFEM CZ User’s Meeting

31. Hexa meshing • Multi-block structured Geometry Blocking Mesh CADFEM CZ User’s Meeting

32. Auto 2-D blocking approach • Each Rectangular surface gets a mapped block. • Arbitrary surfaces get free blocks. • Blocks are independent of surface topology (morphable). • Geometry recognition is used to group potentially problem surfaces. Mapped block Free block CADFEM CZ User’s Meeting

33. Hex or hex dominant meshes • Multiple automatic pathways to high quality all hex or hex dominant meshes. • Auto surface blocking followed by auto volume blocking. • Direct block decomposition method. • Auto surface blocking into surface meshing into hex dominant volume meshing. • Hexa tools can be used to assist either the surface blocking or the volume blocking. • Better parametric association • Hybrid meshing framework CADFEM CZ User’s Meeting

34. Auto blocking from surface blocking • Start from CAD surfaces. • Generate Auto 2-D blocks based on surfaces • Generate Auto 3-D blocks by filling in 2-D blocks with Hex dominant mesher • Automatically create mesh spacing and mesh with existing Hexa techniques. • Results in a high-quality all hex mesh. All Hex CADFEM CZ User’s Meeting

35. True automatic blocking Produces great blocking but sensitive to geometric details CADFEM CZ User’s Meeting

36. Hex meshing: Hex dominant mesher • Start from CAD geomety • Generate all quad surface mesh as before • Automatically fills surface mesh with uniform hex dominant mesh • User can then edit the hex dominant mesh by automatic smoothing and mesh editing HEXA_8 : 4849 PENTA_6 : 287 PYRA_5 : 640 TETRA_4 : 313 CADFEM CZ User’s Meeting

37. HEXA: System level Hexa will do the bookkeeping to keep track of the connectivity of hybrid meshes. • Structured blocks. • Extruded blocks • All Quad • Quad + 1 Tri • Quad dominant • All Tri • Unstructured blocks: • Filled by Tetra • Filled by Hex-Dominant mesher • Filled by Delaunay mesher. CADFEM CZ User’s Meeting

38. Final remarks • Thank you! • Questions? CADFEM CZ User’s Meeting