[laouichi sif]

When I tried to check my mesh using the commend (checkMesh -allTopology -allGeometry) I had this message (Failed 1 mesh checks)
My model is a car I used gmsh for the geometry and a tetrahedral mesh with 3 box fields
The full chechMesh response is :



/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.1.1-221db2718bbb
Exec : checkMesh -allTopology -allGeometry
Date : Mar 21 2016
Time : 16:54:29
Host : "seif-Inspiron-N5110"
PID : 6533
Case : /home/seif/Desktop/FoamExo/poly
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
points: 179866
internal points: 0
edges: 626707
internal edges: 88521
internal edges using one boundary point: 0
internal edges using two boundary points: 88521
faces: 625295
internal faces: 266975
cells: 178454
boundary patches: 6
point zones: 0
face zones: 0
cell zones: 1

Overall number of cells of each type:
hexahedra: 0
prisms: 178454
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Cell to face addressing OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Topological cell zip-up check OK.
Face-face connectivity OK.
<<Writing 1412 cells with with two non-boundary faces to set twoInternalFacesCells
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology Bounding box
frontAndBack 356908 179866 ok (non-closed singly connected) (-297.817 0 0) (1983.46 858.095 40)
top 58 118 ok (non-closed singly connected) (-297.817 858.095 0) (1983.46 858.095 40)
inlet 22 46 ok (non-closed singly connected) (-297.817 0 0) (-297.817 858.095 40)
bttom 628 1258 ok (non-closed singly connected) (-297.817 0 0) (1983.46 0 40)
outlet 22 46 ok (non-closed singly connected) (1983.46 0 0) (1983.46 858.095 40)
car 682 1364 ok (non-closed singly connected) (-0.0471055 1.47399 0) (297.845 83.7705 40)

Checking geometry...
Overall domain bounding box (-297.817 0 0) (1983.46 858.095 40)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (1.14653e-18 3.09871e-17 -2.51217e-23) OK.
Max cell openness = 2.13669e-16 OK.
Max aspect ratio = 309.888 OK.
Minumum face area = 0.0554911. Maximum face area = 2271.43. Face area magnitudes OK.
Min volume = 2.21964. Max volume = 40108.1. Total volume = 7.76016e+07. Cell volumes OK.
Mesh non-orthogonality Max: 41.1748 average: 6.15288
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.60236 OK.
Coupled point location match (average 0) OK.
Face tets OK.
Min/max edge length = 0.327236 56.7859 OK.
All angles in faces OK.
Face flatness (1 = flat, 0 = butterfly) : average = 1 min = 1
All face flatness OK.
Cell determinant (wellposedness) : minimum: 0 average: 2.59366e-36
***Cells with small determinant found, number of cells: 178454
<<Writing 178454 under-determined cells to set underdeterminedCells
Concave cell check OK.

Failed 1 mesh checks.

End





The geometry of the car is in the attachments

Thank you !!

[laouichi sif]

I tried to run " checkMesh -allTopology" I found that "the Mesh ok"
but when I run "checkMesh -allGeometry" I found "Failed 1 mesh checks"
the problem was in "Cell determinant (wellposedness)" .I get a huge number of cells with small determinant that are written to a faceSet undeterminedCells

(( Cell determinant (wellposedness) : minimum: 0 average: 2.46593e-36
***Cells with small determinant found, number of cells: 190460
<<Writing 190460 under-determined cells to set underdeterminedCells ))

Has anyone some experience with this issue? Does this even effect the simulation?
Or is there any solution to this problem?
please help me !!

[Maimouna]

Dear Sif,

have you got your question answer, I'm also looking for the same qustion. If you got the answer shear me your experience please.

Kind regards

Maimouna