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-   -   gmsh + orientation? (http://www.cfd-online.com/Forums/openfoam-pre-processing/101847-gmsh-orientation.html)

sukye May 15, 2012 12:56

gmsh + orientation?
 
I am using CentFoam at my CentOS machine.

The current project is to test the cavity tutorial with a different geometry, ie the front and back walls are half circles instead of the original rectangles.

gmsh creates the 3D mesh, ie the msh file. Tested it with checkMesh and the error message is:

Code:

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
    points:          2038
    faces:            18720
    internal faces:  17740
    cells:            9115
    boundary patches: 4
    point zones:      0
    face zones:      0
    cell zones:      1

Overall number of cells of each type:
    hexahedra:    0
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    9115
    polyhedra:    0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
    Patch              Faces    Points  Surface topology                 
    top                76      78      ok (non-closed singly connected) 
    bottom              124      126      ok (non-closed singly connected) 
    back                390      246      ok (non-closed singly connected) 
    front              390      246      ok (non-closed singly connected) 

Checking geometry...
    Overall domain bounding box (0 -4.99358 0) (10 0 0.1)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (1.17825e-19 1.39248e-18 1.56129e-16) OK.
 ***High aspect ratio cells found, Max aspect ratio: 8.98903e+197, number of cells 3
  <<Writing 3 cells with high aspect ratio to set highAspectRatioCells
    Minumum face area = 0.000117197. Maximum face area = 0.195124.  Face area magnitudes OK.
    Min volume = 1.33333e-300. Max volume = 0.00325207.  Total volume = 3.92027.  Cell volumes OK.
    Mesh non-orthogonality Max: 85.6854 average: 54.7686
  *Number of severely non-orthogonal faces: 4053.
    Non-orthogonality check OK.
  <<Writing 4053 non-orthogonal faces to set nonOrthoFaces
 ***Error in face pyramids: 12 faces are incorrectly oriented.
  <<Writing 12 faces with incorrect orientation to set wrongOrientedFaces
    Max skewness = 1.32807 OK.
    Coupled point location match (average 0) OK.

Failed 2 mesh checks.

End

I am also copying the .geo file here:
Code:

cl1 = 0.5;
Point(1) = {0, 0, 0, cl1};
Point(2) = {10, 0, 0, cl1};
Point(3) = {5, 0, 0, cl1};
Point(4) = {0, 0, 0.1, cl1};
Point(5) = {10, 0, 0.1, cl1};
Point(6) = {5, 0, 0.1, cl1};
Line(1) = {1, 2};
Line(2) = {4, 5};
Circle(3) = {1, 3, 2};
Circle(4) = {4, 6, 5};
Line(5) = {1, 4};
Line(6) = {2, 5};
Line Loop(10) = {-2, -5, 1, 6};
Plane Surface(10) = {10};
Line Loop(12) = {-6, -3, 5, 4};
Plane Surface(12) = {12};
Line Loop(14) = {2, -4};
Plane Surface(14) = {14};
Line Loop(16) = {3, -1};
Plane Surface(16) = {16};
Surface Loop(68) = {10, 12, 14, 16};
Volume(68) = {68};
Physical Surface("front") = {16};
Physical Surface("back") = {14};
Physical Surface("bottom") = {12};
Physical Surface("top") = {10};
Physical Volume("internal") = {68};


sukye May 15, 2012 13:08

Floating point exception
 
It is possible OpenFOAM still works when checkMesh finds errors. Right?

So I continue to gmshToFoam the msh file, modify the initial p, U, and boundary accordingly. Then run icoFoam,

Code:

Create time

Create mesh for time = 0

Reading transportProperties

Reading field p

Reading field U

Reading/calculating face flux field phi


Starting time loop

Time = 0.005

Courant Number mean: 0 max: 0
DILUPBiCG:  Solving for Ux, Initial residual = 1, Final residual = 2.36138e-06, No Iterations 3
DILUPBiCG:  Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG:  Solving for p, Initial residual = 1, Final residual = 9.74703e-07, No Iterations 227
time step continuity errors : sum local = 2.9243e-11, global = -9.77389e-23, cumulative = -9.77389e-23
#0  Foam::error::printStack(Foam::Ostream&) in "$RUN/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1  Foam::sigFpe::sigHandler(int) in "$RUN/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2  __restore_rt at sigaction.c:0
#3  void Foam::fvc::surfaceIntegrate<double>(Foam::Field<double>&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "$RUN/platforms/linux64GccDPOpt/bin/icoFoam"
#4  Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::surfaceIntegrate<double>(Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "$RUN/platforms/linux64GccDPOpt/bin/icoFoam"
#5  Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<double>(Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "$RUN/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#6  Foam::fv::gaussLaplacianScheme<double, double>::fvmLaplacian(Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "$RUN/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#7  Foam::fv::laplacianScheme<double, double>::fvmLaplacian(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "$RUN/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#8  Foam::tmp<Foam::fvMatrix<double> > Foam::fvm::laplacian<double, double>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::word const&) in "$RUN/platforms/linux64GccDPOpt/bin/icoFoam"
#9  _ZN4Foam3fvm9laplacianIddEENS_3tmpINS_8fvMatrixIT_EEEERKNS_14GeometricFieldIT0_NS_12fvPatchFieldENS_7volMeshEEERKNS7_IS4_S9_SA_EE.constprop.416 at icoFoam.C:0
#10  main in "$RUN/platforms/linux64GccDPOpt/bin/icoFoam"
#11  __libc_start_main in "/lib64/libc.so.6"
#12  Foam::regIOobject::writeObject(Foam::IOstream::streamFormat, Foam::IOstream::versionNumber, Foam::IOstream::compressionType) const in "$RUN/platforms/linux64GccDPOpt/bin/icoFoam"
Floating point exception

I also find those files are not empty:
highAspectRatioCells
nonAlignedEdges
nonOrthoFaces
wrongOrientedFaces


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