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[Gambit] inverted elements / negative volume

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Old   February 20, 2010, 12:54
Default [Gambit] inverted elements / negative volume
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Jouke de Baar
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Hi,

In Gambit I ran into a strange problem. When I mesh a certain face, the grid is out of the plane of the face. I get the following message:

"ERROR: ACIS error 43001 : coincident face_face_ints with different body vertices"

The strange thing is that I had no difficulties at all with coarser meshes for the exact same geometry.

However, I can still mesh the associated volume (with some highly skewed elements) and write a .msh file. I can read it in Fluent, but the grid check fails: the problem appears to be that I have 6171095 right-handed and 26 left-handed faces. Still, in Fluent the grid contains the correct number of elements. I can initialize, but when I try to iterate Fluent returns:

"Error: divergence detected in AMG solver: pressure correction"

So, I'm pretty sure something is wrong with this face. It appears to cause some troubles, such that I can't iterate in Fluent.

Furthermore, if I decrease the element size at the (distorted grid) face edge, Gambit will mesh the face but won't mesh the associated volume anymore:

"inverted elements (negative VOLUME)"

I really hope somebody can help me out here. Especially since the results on the coarser grids looked so promising.

Thanks!

Update:
I tried TUI: /grid/modify-zones/repair-face-handednes
This returned: "Left-handed faces can't be converted to right-handed faces. All face nodes have the right order, but the mesh probably contains non-convex cells."

Last edited by jack1980; February 20, 2010 at 13:18. Reason: update
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Old   February 22, 2010, 02:50
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Maxime Perelli
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I would try to split your face which gives you trouble.
Enforcing the presence of edge(s) on the surface may help and solve your problem.
Already experienced this case
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