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-   -   [ICEM] Tetra Tumors (http://www.cfd-online.com/Forums/ansys-meshing/70817-tetra-tumors.html)

rajeshps December 7, 2009 07:26

Tetra Tumors
 
I am getting very big Cells( out of Limits with very bad quality) inside the domain while using Delauny Method for generating Volume mesh from Surface Mesh.

Is it a problem with ICEM or Any Bug with the Software/Memmory Issues. Is there any Way for Avoiding this.

Thanks in Advance
Raj

PSYMN December 8, 2009 13:02

Delaunay TGlib with AFT in 12.1
 
I am a little suspicious of this question because you already know we call them tetra tumors… ;) Most people who know that already spoke to us and know the answer. If you just guessed that name, then we think alike and perhaps also chose the same names for our children or dog.;)

This was a rarely occurring problem inherent in the Delaunay algorithm. It is very sensitive to the surface mesh so you could modify it only slightly and it would go away or perhaps move to somewhere else. I have a very technical explanation from the developer that I can dig up if anyone is really interested, but let’s just move on.

You can edit your way out of tetra tumors. Use subsets to find the bad cells, then add a few layers of volume elements and delete the clump. Then run Delaunay again with the option to fill holes in volume mesh. This would just run Delaunay in the voids where the tumor was and not redo the entire mesh.

However, now that 12.1 is available, just get that instead. Under Delaunay in 12.1 there is a TGlib option. I think the TGlib volume transition is too sudden (with default settings), so I recommend also turning on the AFT option under the global tetra params. This “Advancing Front” TGlib Delaunay option does not have this Tetra tumor problem and gives a great mesh in less time. It is now my standard bottom up tetra method.:cool:


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