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-   -   Problems on Tetrahedra to Polyhedra using polyDualMesh on concave surface object (http://www.cfd-online.com/Forums/openfoam-pre-processing/62051-problems-tetrahedra-polyhedra-using-polydualmesh-concave-surface-object.html)

chnrdu July 23, 2008 12:38

I'd like to using OpenFOAM wit
 
I'd like to using OpenFOAM with polyhedra mesh to simulate a flow field in a pipe connected volume, like the image:
http://www.cfd-online.com/OpenFOAM_D...ges/1/8457.png
I use salome to generate this mesh with netgen(1d-2d-3d)

I have set up the boundaries as independent as each surface is a boundary, then convert it to polyhedra using polyDualMesh, but checkMesh said that there are several concave faces and wrong oriented faces:

http://www.cfd-online.com/OpenFOAM_D...ges/1/8458.png

the black colored faces is concave faces which are just around the connection edge of the two near boundaries.

However, I set some surfaces together as one boundaries including the neighbor surfaces with concave angle. I can converted it to polyhedra without errors, but the original edge between the concave surfaces becomes to several faces with polygon, so it loses the geometry information.

http://www.cfd-online.com/OpenFOAM_D...ges/1/8459.png

My problem is: how to convert tetra to polymesh avoiding concave faces without losing geometric infomation like such volume?

Thank you in advance.

Martin/Run Du

bfa July 7, 2009 02:19

Hello Martin,
I just recently read your post. Did you by now find a solution to your problem? 'Cause I'm having trouble with the same effect as you describe above.

Regards,
Bjoern

jbf July 18, 2009 12:58

trick with polyDualMesh
 
Quote:

Originally Posted by bfa (Post 221705)
Hello Martin,
I just recently read your post. Did you by now find a solution to your problem? 'Cause I'm having trouble with the same effect as you describe above.

Regards,
Bjoern


Hi ! I had exactly the same problem when using polyDualMesh, ie a loss of the geometrical informations... but I found a trick to avoid this problem : I use a mesh made of only one patch, then I use polyDualMesh with 0 angle, and finaly I divide the single patch with autoPatch. Now I have a good shape for my dual mesh... but I have a new problem using refineWallLayer. For some surfaces mesh I got the following message :
"achorpoints and nonanchorpoints are geometrically on same side!" Do you have an idea to solve this problem ? Does it come from the original mesh ?
Sincerely,
JB


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