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-   -   gmshToFoam warning messages (http://www.cfd-online.com/Forums/openfoam-meshing-open/98573-gmshtofoam-warning-messages.html)

matt.mech.eng March 14, 2012 03:00

gmshToFoam warning messages
 
Hi guys,

I have just generated my own mesh to use in the bubbleFoam, bubbleColumn tutorial in OF2.0.1. I wanted to try and play around with the geometry in the tute so that I can get some preliminary 2d results from which to build a model..

I have generated the mesh in gmsh and copied it into the case directory. I then ran gmshToFoam from the case directory to convert the mesh to OpenFOAM and I get the following 2 warning messages:

--> FOAM Warning :
From function polyMesh:: polyMesh(... construct from shapes...)
in file meshes/polyMesh/polyMeshFromShapeMesh.C at line 614
Found 3041 undefined faces in mesh; adding to default patch.
Finding faces of patch 0

Can someone please shed some light on the possible causes of such an error?


Kind Regards

Matt

matt.mech.eng March 14, 2012 05:55

1 Attachment(s)
I had a look at the statistics for the mesh generated in gmsh, the .msh file and the foam terminal output..

I can see that the .msh file has 4456 elements listed under the $Elements tag yet in stats there are only 1448 prisms...

What other elements does the $Elements tag include?? It is clear that this is where the error is coming from ie the 3008 (4456-1448=3008) undefined faces!!!!

Can someone shed some light on this??

Thanks

Matt

anon_a March 14, 2012 07:03

EDIT: I just saw your screenshot with the extra information and removed my previous answer to avoid misleading you, sorry :-)

Out of curiosity, have you visualized these defaultFaces in paraFoam? what do they look like? do they really belong to your boundary?
Also, I think that the 2D elements (i.e. faces of each 3D element) such as the triangles and quads are also counted in 4456, right?

matt.mech.eng March 14, 2012 08:13

Yes I think the 4456 elements listed in the .msh file under the $Elements tag includes 2d elements ie triangles and quadrangles (2896 and 112 respectively) ie it is these faces that are not being defined... It seems that the gmshToFoam utility is reading the element faces which are listed in the .msh file as well as the 3d elements.

I have visualized the resultant foam mesh in parafoam and it seems ok to me..

I run the solver on the mesh and everything seems fine it's just that the error blows up and the solver crashes prior to finishing for all time steps set in controlDict.. I don't think so but maybe the mesh is having something to do with this?


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