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[Gmsh] STL->GMSH->simpleFoam

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Old   January 24, 2013, 08:28
Default STL->GMSH->simpleFoam
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David Doose
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Hi,

I'm looking for a simple example in which:
- the mesh is generated with gmsh using an STL object;
- the computation is made with simpleFoam.

In practice, my attempts always lead to a "Floating point exception"...
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Old   January 24, 2013, 16:34
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Bruno Santos
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Greetings David,

Have you tried to replicate one of OpenFOAM's tutorials for simpleFoam, but using a mesh generated with Gmsh?

Have you checked the validity of your mesh after conversion? Try:
Code:
checkMesh
checkMesh -allGeometry -allTopology
Best regards,
Bruno
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Old   January 25, 2013, 05:37
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David Doose
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In fact, the simple "checkMesh" is Ok, the Topology (-allTopology) is also OK, but the the geometry check (-allGeometry) failed.

How can I modify the gmsh file to solve this kind of problem ?

Code:
>     Face tets OK.
>     Min/max edge length = 0.168466 10.198 OK.
>     All angles in faces OK.
>     All face flatness OK.
>     Cell determinant (wellposedness) : minimum: 0 average: 1.34053
>  ***Cells with small determinant found, number of cells: 646
>   <<Writing 646 under-determined cells to set underdeterminedCells
>     Concave cell check OK.
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Old   January 26, 2013, 14:51
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Hi David,

Mmm... cell determinant zero can lead to some problems... Run the following command:
Code:
foamToVTK -cellSet underdeterminedCells
Then open the file "underdeterminedCells*.vtk" which should be inside the folder "VTK". It will show you where the cells with very small determinant are located.

edit: sorry, I forgot to mention that once you see the bad cells, you try and increase refinement or orientation on the zone where those cells are having problems.

Best regards,
Bruno
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Last edited by wyldckat; January 26, 2013 at 14:53. Reason: see "edit:"
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