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-   -   Face ordering problem for nonrectangular cyclic boundary conditions (https://www.cfd-online.com/Forums/openfoam-meshing-other/61689-face-ordering-problem-nonrectangular-cyclic-boundary-conditions.html)

 cfdmarkus September 19, 2008 11:08

Hi, I am trying to simulate

Hi,

I am trying to simulate the flow in a planar channel with streamwise periodic hills on the lower wall. The flow domain has planar, cyclic boundary conditions in streamwise and spanwise directions.
Using cyclic boundary conditions in streamwise direction works just fine, however, a face ordering problem exists when I use cyclic boundaries in spanwise direction.

*****************************************
face 0 area does not match neighbour 722 by 37.8947% -- possible face ordering problem.
patch:CYCLICSYMM my area:0.00280653 neighbour area:0.00411868 matching tolerance:0.001
Mesh face:41515 vertices:4((0 0.0526316 0) (0.0526316 0.0540166 0) (0.0526316 0 0) (0 0 0))
Neighbour face:42237 vertices:4((1 0 0) (1 0.0789474 0) (1.05263 0.0775623 0) (1.05263 0 0))
Rerun with cyclic debug flag set for more information.

From function cyclicPolyPatch::calcTransforms()
in file meshes/polyMesh/polyPatches/constraint/cyclic/cyclicPolyPatch.C at line 150.
****************************************

For the same case with the hills removed (simple planar channel flow with cyclic BC in streamwise and spanwise direction) this problem does not exist. The only difference between the two cases is that without the hills in place, the faces in spanwise directions are rectangular and with the hills in place, the faces are non-rectangular.

I also tried to export the grid with two separate boundary faces in spanwise direction and then tried to combine the faces into a cyclic patch using createPatch. Unfortunatley, this always resulted in a crash of createPatch.

Does anybody know why the face ordering problem suddenly arises when I am using non-rectangular patches as cyclic BC and more importantly, how can I solve this face ordering problem?

Best regards,
Markus

 chegdan September 26, 2008 11:13

I have the same problem, its a

I have the same problem, its always when I am trying to use a 3D mesh with a cyclic bc. Try renumberMesh and see what happens. Although I was not able to have any better luck when I did this. I did also try the createPatch utility and it hasn't worked in OF 1.5 for me yet, but did in 1.4.1-dev.

 maysmech September 28, 2010 12:45

i have same problem :(

 prameelar August 17, 2011 15:07

Check with the vertices values.. there is a difference in betwwen these points.

"4((0 0.0526316 0) (0.0526316 0.0540166 0) (0.0526316 0 0) (0 0 0))
4((1 0 0) (1 0.0789474 0) (1.05263 0.0775623 0) (1.05263 0 0)) ".

Hope it helps.

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