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how to create cyclic from 2 boundaries in Openfoam 1.7.1

Hi everyone,

I wonder if you could help me please with the problem concerning cyclic boundary with OpenFOAM 1.7.1.

I have a quite simple geometry for an airfoil and would like to set up periodic boundary conditions on the 2 vertical boundaries. I'm trying to create the periodic boundary from 2 boundaries (''wall'') with createPatch but I've got errors:

Moving faces from patch new_wall0 to patch 7
Moving faces from patch new_wall1 to patch 7

Doing topology modification to order faces.

cyclicPolyPatch::order : Writing half0 faces to OBJ file "new_wall_half0_faces.obj"
cyclicPolyPatch::order : Writing half1 faces to OBJ file "new_wall_half1_faces.obj"
cyclicPolyPatch::order : Dumping currently found cyclic match as lines between corresponding face centres to file "new_wall_faceCentres.obj"
--> FOAM Serious Error :
From function cyclicPolyPatch::order(const primitivePatch&, labelList&, labelList&) const
in file meshes/polyMesh/polyPatches/constraint/cyclic/cyclicPolyPatch.C at line 1566
Patch:new_wall : Cannot match vectors to faces on both sides of patch
Perhaps your faces do not match? The obj files written contain the current match.
Continuing with incorrect face ordering from now on!

--> FOAM FATAL ERROR:
face 5240 area does not match neighbour 133908 by 0.00101172% -- possible face ordering problem.
patch:new_wall my area:0.000254184 neighbour area:0.000254182 matching tolerance:1e-05
Mesh face:264077 vertices:4((-0.0707825 -0.9 0.03) (-0.068948 -0.9 0.03) (-0.068948 -0.761442 0.03) (-0.0707825 -0.761442 0.03))
Neighbour face:392745 vertices:4((-0.0707827 -0.9 0) (-0.0707827 -0.761442 0) (-0.0689482 -0.761442 0) (-0.0689482 -0.9 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 179.

FOAM exiting

thanks

Quote:

Originally Posted by vsflap (Post 396630)

Hi vsflap,

I am also having a similar problem. Were you able to figure out the solution ? It would be very helpful to me :)

Hi vsflap,
I think you made some mistake in defining cyclic BC. In my case i used it for straight channel where inlet and outlet are my periodic BCs. I defined as follows:

Quote:

leftWall
{
type cyclic;
neighbourPatch rightWall;
faces
(
(0 4 7 3)
);
}
rightWall
{
type cyclic;
neighbourPatch leftWall;
faces
(
(2 6 5 1)
);
}

Hope this will help

Regards
Reddy

Hi Reddy,

I figured out the problem, it was in the grid definition in blockmeshdict. It works now:)
Also, can you tell me what boundary conditions did you use for p and U ?
I am trying to use the fan bc, but haven't figured it out yet. I have a laminar flow in a rectangular channel with a cylinder inside it.

Thanks!

Dear Shadowfax
I used cyclic type BC for p and U.
For p:

Code:

leftWall

    {

        type            cyclic;

        nFaces          40;

        startFace       157960;

        matchTolerance  0.0001;

        neighbourPatch  rightWall;

    }

    fixedWalls

    {

        type            zeroGradient;

    }

    rightWall

    {

        type            cyclic;

        nFaces          40;

        startFace       162000;

        matchTolerance  0.0001;

        neighbourPatch  leftWall;

    }

    frontAndBack

    {

        type            empty;

    }

For U:

Code:

leftWall

    {

        type            cyclic;

        nFaces          40;

        startFace       157960;

        matchTolerance  0.0001;

        neighbourPatch  rightWall;

    }

    fixedWalls

    {

        type            fixedValue;

        value           uniform (0 0 0);

    }

    rightWall

    {

        type            cyclic;

        nFaces          40;

        startFace       162000;

        matchTolerance  0.0001;

        neighbourPatch  leftWall;

    }

    frontAndBack

    {

        type            empty;

    }

Regards
M Reddy