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-   -   Failed 1 mesh checks (

Nico A. June 9, 2011 10:47

Failed 1 mesh checks
Hello everybody,

I want to simulate the flow around a sphere. For that, I created the mesh in Gambit which looks quite good to me. Then I converted the mesh with fluent3DMeshToFoam with OpenFOAM 1.7.0.
By using checkMesh, I got the following message which I can't interpret:

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
    points:          138112
    faces:            400500
    internal faces:  387000
    cells:            131250
    boundary patches: 4
    point zones:      0
    face zones:      1
    cell zones:      1

Overall number of cells of each type:
    hexahedra:    131142
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:    108

Checking topology...
    Boundary definition OK.
    Point usage OK.
  <<Found 27 neighbouring cells with multiple inbetween faces.
    Upper triangular ordering OK.
  <<Writing 54 unordered faces to set upperTriangularFace
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
    Patch              Faces    Points  Surface topology                 
    outlet              625      676      ok (non-closed singly connected) 
    rest                8500    8600    ok (non-closed singly connected) 
    cylinder            3750    3752    ok (closed singly connected)     
    inlet              625      676      ok (non-closed singly connected) 

Checking geometry...
    Overall domain bounding box (0 0 0) (8 2 2)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (-9.45575e-17 -2.58425e-18 -7.56937e-18) OK.
 ***Open cells found, max cell openness: 0.878109, number of open cells 108
  <<Writing 108 non closed cells to set nonClosedCells
    Minumum face area = 8.6151e-05. Maximum face area = 0.0105716.  Face area magnitudes OK.
    Min volume = 1.37781e-06. Max volume = 0.000845729.  Total volume = 31.9665.  Cell volumes OK.
    Mesh non-orthogonality Max: 53.2154 average: 19.1478
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 1.02786 OK.

Failed 1 mesh checks.


Actually I created a structured grid in Gambit, but looking at it in ParaView there are some unstructured parts after the conversion, as written above.
I also tried to import the mesh into Fluent and I got an error: Null Domain Pointer.

Does anyone have a clue?
With kind regards, Nico

-mAx- June 10, 2011 02:59

try with fluentMeshToFoam
Paraview issue, is just a graphic bug.
But if you cannot import your grid in fluent, I assume there is someting wrong.
no warning while exporting your mesh from gambit?

Nico A. June 10, 2011 05:14

I checked the mesh in Gambit and everything was fine, also no errror while exporting.
With fluentMeshToFoam I got the following:

Create time

Dimension of grid: 3
Number of points: 138112
Reading points
number of faces: 400500
Reading mixed faces
Reading mixed faces
Reading mixed faces
Reading mixed faces
Reading mixed faces
Number of cells: 131250
Other readCellGroupData: 2 1 200b2 1 4
Reading uniform cells
Read zone1:2 name:fluid patchTypeID:fluid
Reading zone data
Read zone1:3 name:outlet patchTypeID:pressure-outlet
Reading zone data
Read zone1:4 name:rest patchTypeID:symmetry
Reading zone data
Read zone1:5 name:cylinder patchTypeID:wall
Reading zone data
Read zone1:6 name:inlet patchTypeID:velocity-inlet
Reading zone data
Read zone1:8 name:default-interior patchTypeID:interior
Reading zone data


dimension of grid: 3
Creating shapes for 3-D cells

Cannot find match for face 5.
Model: hex model face: 4(1 2 6 5) Mesh faces:
4(4586 4610 4609 4585)
4(4609 4585 4586 4610)
4(4585 20031 20607 4586)
4(20583 4610 4586 20607)
4(20031 4585 4609 20007)
4(4610 20583 20007 4609)
Matched points: 8(4586 20607 20031 4585 4610 20583 20007 4609)

    From function create3DCellShape(const label cellIndex, const labelList& faceLabels, const labelListList& faces, const labelList& owner, const labelList& neighbour, const label fluentCellModelID)
    in file create3DCellShape.C at line 280.

FOAM aborting

#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam170/lib/linux64GccDPOpt/"
#1  Foam::error::abort() in "/opt/openfoam170/lib/linux64GccDPOpt/"
 in "/opt/openfoam170/applications/bin/linux64GccDPOpt/fluentMeshToFoam"
 in "/opt/openfoam170/applications/bin/linux64GccDPOpt/fluentMeshToFoam"
#4  __libc_start_main in "/lib/"
 in "/opt/openfoam170/applications/bin/linux64GccDPOpt/fluentMeshToFoam"

-mAx- June 10, 2011 05:23

Just to check: create another mesh with Gambit (full tetra, or tetra-hexcore)
export, and load it into Foam.
Check if you still have problem.
PS: Something is weird with those 108 polyhedra, since Gambit isn t able to create Polyhedra

Nico A. June 10, 2011 10:19

Thank you max, for your quick replies. I checked a new mesh, just with a few more cells and it worked. I still dont know why this problems appears but now I can do my simulations on it.

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