problem in prism layer generation
 

Hi guys,

I follow the tutorial of iCEM 11.0 to generate tetra mesh and then want to creat prism layer. But I fail again and agin with errors like these:

face at 118583 173622 230139 has one volume neighbor and no shell element vt1 loc = 15.1891 18.1678 -27.5124 3 elements at face 181849 224649 224804, not all tets PYRA_5 TETRA_4 TETRA_4 PYRA_5 PENTA_6 PENTA_6 PENTA_6 PENTA_6 PYRA_5 TETRA_4 TETRA_4 PYRA_5 TETRA_4 PYRA_5 TETRA_4 PYRA_5 PENTA_6 PENTA_6 PYRA_5 TETRA_4 TETRA_4 some tetrahedra occupy the same volume and that couldn't be fixed .... and 27 more error messages ... orientation errors! writing out prism layer 1 done initializing directions from levelset norm 5805 prism_nodes Assertion failed: has_volume_elements == 0, file compute_marching_dir.C, line 559

This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Application is finished. Error: prism terminated prematurely

Anybody has any idea? Thanks!!

Re: problem in prism layer generation
 

First make sure your tetra mesh passes all errors and possible problems checks. Sounds like the tet mesh may have some problems.

Re: problem in prism layer generation
 

Hi,

These sort of errors usually occur when the mesh is not fine enough to resolve the geometry or the underlying mesh is poor quality. The fix is finer mesh and/or better quality mesh.

Glenn Horrocks

Hi

I have had the exact same problem.
Unfortunately, I have not been able to resolve this situation.
My mesh contains 4 Millions tet elements so I suppose it could be fine enough.
But indeed, it works when I ask ICEM to prism only very simple surfaces, so it tends to prove Glenn Horrocks' point.

Please let me know here if any solution has been found except a perfect mesh, which usually never happens in industry

---JOKE---

The solution is training and experience. You can earn a good wage as a CFD engineer and the reason is because it is not easy.

A collegue has found a way to avoid the crash.
This crash happens after extruding the first prism layer because the quality has diminished. Therefore, an easy way to compute prism boundary layer is :
- compute only one layer
- split it (split prism option)

My collegue always used this method so that the prism are more regular and gradients better computed.

Hoping this will help,

---JOKE---