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Converting SnappyHexMesh-Grids without Polyhedra

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Old   November 3, 2015, 08:44
Default Converting SnappyHexMesh-Grids without Polyhedra
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BastiL
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Hello all,

I am experimenting to use snappyHexMesh for some other applications. Therefore, I need to export a mesh without polyhedral cells. I tried the following with the motorbike tutorial:
Code:
foamToVTK -ascii
vtkUnstructuredToFoam
foamMeshToFluent
Step 1: convert snappyHexMesh-File to VTK to get rid of polyhedral cells (only application I am aware of that does polyhedral decomposition)
Step 2: Get back to OpenFoam
Step 3: Export for further usage, e.g. to Fluent

Step 3 tells me:
Code:
Writing Header
--> FOAM Warning : 
    From function void fluentFvMesh::writeFluentMesh() const
    in file fluentFvMesh.C at line 257
    foamMeshToFluent: cell shape for cell 1098 only supported by Fluent polyhedral meshes.
    Suppressing any further messages for polyhedral cells.
End
I don't expect this. And after checking the mesh there are really polyhedral cells left. However, some cells where definitely decomposed into Tet/Pyramid as I can see. Si I don't understand what's going on there. Any idea or some other way?

Last edited by bastil; November 3, 2015 at 12:24.
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Old   November 4, 2015, 08:09
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BastiL
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I ran some checkMesh on it. For the snapped mesh it looks like this:

Code:
Overall number of cells of each type:
    hexahedra:     307005
    prisms:        7281
    wedges:        940
    pyramids:      6
    tet wedges:    1649
    tetrahedra:    58
    polyhedra:     35158
    Breakdown of polyhedra by number of faces:
        faces   number of cells
            4   3964
            5   6536
            6   5490
            7   2994
            8   1309
            9   10590
           10   15
           11   8
           12   2351
           13   2
           15   1621
           17   1
           18   275
           21   2
and after conversation:

Code:
Mesh stats
    points:           439799
    faces:            1848069
    internal faces:   1779521
    cells:            682986
    faces per cell:   5.31137
    boundary patches: 1
    point zones:      0
    face zones:       0
    cell zones:       0
Overall number of cells of each type:
    hexahedra:     307005
    prisms:        3715
    wedges:        940
    pyramids:      272475
    tet wedges:    1649
    tetrahedra:    93636
    polyhedra:     3566
    Breakdown of polyhedra by number of faces:
        faces   number of cells
            5   3566
Seems like a number of polyhedral cells is not decomposed by foamToVTK.
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