cyclic boundary condition

xxxx · March 13, 2013, 13:13

Hello everybody.

I'm trying to understand how cyclic BC works in OF211.

I built a very simple mesh and imposed the cyclic BC on opposite faces. These faces are axis-symmetrical with respect to z-axis.
When I solve the case i see that the cyclic BC doesn't work as i expect it to do.
I post a snapshot of the cyclic faces.
I would like faces A and C to be connected and B&D too, but what i get seems to be A connected to D and B connected to C.
Can someone help me please?

NickolasPl · March 14, 2013, 17:41

Hello,

These two patches must be physically connected in some way. In blockmesh file you have to declare through the CYCLIC the projection of one patch to the other with some accuracy through the tolerance number. Be careful that the points on each patch the points should be exactly symmetrical otherwise you will problems with the blockmesh-ing. Then you simply set the BC's on 0 folder as CYCLIC on the variables you want to solve.

Nickolas

xxxx · March 16, 2013, 03:25

Thank you for your answer.
Actually my mesh is made in open Salome and I import it via ideasUnvToFoam.
The points on the two faces are symmetrical (the mesh is structured).
Anyway I solved the problem by using createPatchDict. I convert the two patches in new patches connected each other and substitute them to the old polyMesh.
It works but I would like to know if there is a better way to do this.

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March 14, 2013, 17:41		#2
NickolasPl Member Nickolas P Join Date: Oct 2010 Location: Greece Posts: 30 Rep Power: 16	Hello, These two patches must be physically connected in some way. In blockmesh file you have to declare through the CYCLIC the projection of one patch to the other with some accuracy through the tolerance number. Be careful that the points on each patch the points should be exactly symmetrical otherwise you will problems with the blockmesh-ing. Then you simply set the BC's on 0 folder as CYCLIC on the variables you want to solve. Nickolas

March 16, 2013, 03:25		#3
xxxx Member xxxxx Join Date: Feb 2013 Posts: 34 Rep Power: 13	Thank you for your answer. Actually my mesh is made in open Salome and I import it via ideasUnvToFoam. The points on the two faces are symmetrical (the mesh is structured). Anyway I solved the problem by using createPatchDict. I convert the two patches in new patches connected each other and substitute them to the old polyMesh. It works but I would like to know if there is a better way to do this.