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-   -   [blockMesh] error in cyclic boundary condition (https://www.cfd-online.com/Forums/openfoam-meshing/152249-error-cyclic-boundary-condition.html)

dauri03 April 27, 2015 08:56
error in cyclic boundary condition
 
Hello,
I'm using OpenFoam 2.3.x.
My case has a cyclic boundary condition with 5 faces on each side.
When i do checkMesh an error occurs:

Code:

**Error in coupled point location: 10 faces have their 0th or consecutive vertex not opposite their coupled equivalent. Average mismatch 2.240826614e-18.
  <<Writing 10 faces with incorrectly matched 0th (or consecutive) vertex to set coupledFaces
If i set the second face on each side to a wall boundary, there is no problem.

Any ideas?

Best regards,
Daniel

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  2.3.0                                |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version    2.0;
    format      ascii;
    class      dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 0.001;

vertices
(
    (0 3 0)//0
    (4 3 0)
    (6 3 0)
    (10 3 0)
    (0 1 0)
    (2 -1 0)//5
    (3 0 0)
    (4 0 0)
    (6 0 0)
    (7 0 0)
    (8 -1 0)//10
    (10 1 0)
    (0 -2 0)
    (2 -2 0)
    (4 -2 0)
    (6 -2 0)//15
    (7 -2 0)
    (8 -2 0)
    (10 -2 0)
    (0 -4 0)
    (2 -4 0)//20
    (4 -4 0)
    (6 -4 0)
    (7 -4 0)
    (8 -4 0)
    (10 -4 0)//25
    (0 -40 0)
    (2 -40 0)
    (4 -40 0)
    (6 -40 0)
    (7 -40 0)//30
    (8 -40 0)
    (10 -40 0)

    (0 3 0.1)//33
    (4 3 0.1)
    (6 3 0.1)//35
    (10 3 0.1)
    (0 1 0.1)
    (2 -1 0.1)
    (3 0 0.1)
    (4 0 0.1)//40
    (6 0 0.1)
    (7 0 0.1)
    (8 -1 0.1)
    (10 1 0.1)
    (0 -2 0.1)//45
    (2 -2 0.1)
    (4 -2 0.1)
    (6 -2 0.1)
    (7 -2 0.1)
    (8 -2 0.1)//50
    (10 -2 0.1)
    (0 -4 0.1)
    (2 -4 0.1)
    (4 -4 0.1)
    (6 -4 0.1)//55
    (7 -4 0.1)
    (8 -4 0.1)
    (10 -4 0.1)
    (0 -40 0.1)
    (2 -40 0.1)//60
    (4 -40 0.1)
    (6 -40 0.1)
    (7 -40 0.1)
    (8 -40 0.1)
    (10 -40 0.1)//65

    (0 36 0)//66
    (4 36 0)//67
    (6 36 0)//68
    (10 36 0)//69

    (0 36 0.1)//70
    (4 36 0.1)//71
    (6 36 0.1)//72
    (10 36 0.1)//73
);

blocks
(


    hex (6 7 1 0 39 40 34 33) (10 10 1) simpleGrading (1 1 1)//1
    hex (7 8 2 1 40 41 35 34) (10 10 1) simpleGrading (1 1 1)//2
    hex (8 9 3 2 41 42 36 35) (10 10 1) simpleGrading (1 1 1)//3
    hex (5 6 0 4 38 39 33 37) (10 10 1) simpleGrading (1 1 1)//4
    hex (9 10 11 3 42 43 44 36) (10 10 1) simpleGrading (1 1 1)//5
    hex (12 13 5 4 45 46 38 37) (10 10 1) simpleGrading (1 1 1)//6
    hex (14 15 8 7 47 48 41 40) (10 10 1) simpleGrading (1 1 1)//7
    hex (17 18 11 10 50 51 44 43) (10 10 1) simpleGrading (1 1 1)//8
    hex (19 20 13 12 52 53 46 45) (10 10 1) simpleGrading (1 1 1)//9
    hex (23 24 17 16 56 57 50 49) (10 10 1) simpleGrading (1 1 1)//10
    hex (24 25 18 17 57 58 51 50) (10 10 1) simpleGrading (1 1 1)//11
    hex (26 27 20 19 59 60 53 52) (10 100 1) simpleGrading (1 1 1)//12
    hex (27 28 21 20 60 61 54 53) (10 100 1) simpleGrading (1 1 1)//13
    hex (28 29 22 21 61 62 55 54) (10 100 1) simpleGrading (1 1 1)//14
    hex (29 30 23 22 62 63 56 55) (10 100 1) simpleGrading (1 1 1)//15
    hex (30 31 24 23 63 64 57 56) (10 100 1) simpleGrading (1 1 1)//16
    hex (31 32 25 24 64 65 58 57) (10 100 1) simpleGrading (1 1 1)//17
    hex (0 1 67 66 33 34 71 70) (10 100 1) simpleGrading (1 1 1)//18
    hex (1 2 68 67 34 35 72 71) (10 100 1) simpleGrading (1 1 1)//19
    hex (2 3 69 68 35 36 73 72) (10 100 1) simpleGrading (1 1 1)//20
);

edges
(
);

boundary
(
    inlet
    {
        type patch;
        faces
        (
                (70 71 67 66)
        (71 72 68 67)
        (72 73 69 68)
        );
    }
    outlet
    {
        type patch;
        faces
        (
                (26 27 60 59)
        (27 28 61 60)
        (28 29 62 61)
        (29 30 63 62)
        (30 31 64 63)
        (31 32 65 64)
        );
    }
    fixedWalls
    {
        type wall;
        faces
        (
                (20 21 54 53)
                (21 22 55 54)
        (22 23 56 55)
        (23 16 49 56)
        (16 17 50 49)
        (17 10 43 50)
        (10 9 42 43)
        (9 8 41 42)
        (8 15 48 41)
        (47 48 15 14)
        (47 14 7 40)
        (39 40 7 6)
        (38 39 6 5)
        (13 46 38 5)
        (20 53 46 13)   
        );
    }
    patch0_half0
    {
        type cyclic;
    neighbourPatch patch0_half1;
        faces
    (
            (70 66 0 33)
        (33 0 4 37) 
            (37 4 12 45)
            (45 12 19 52)
        (52 19 26 59)   
    );
    }
    patch0_half1
    {
        type cyclic;
    neighbourPatch patch0_half0;
        faces
    (
            (69 73 36 3)
        (3 36 44 11)
            (11 44 51 18)
                (18 51 58 25)
        (25 58 65 32)   
    );
    }
    frontAndBack
    {
        type empty;
        faces
        (
                (66 67 1 0)
                (67 68 2 1)
        (68 69 3 2)
        (0 1 7 6)
        (1 2 8 7)
        (2 3 9 8)
        (0 6 5 4)
        (3 11 10 9)
        (4 5 13 12)
        (7 8 15 14)
        (10 11 18 17)
        (12 13 20 19)
        (16 17 24 23)
        (17 18 25 24)
        (19 20 27 26)
        (20 21 28 27)
        (21 22 29 28)
        (22 23 30 29)
        (23 24 31 30)
        (24 25 32 31)
        (33 34 71 70)
        (34 35 72 71)
        (35 36 73 72)
        (39 40 34 33)
        (40 41 35 34)
        (41 42 36 35)
        (37 38 39 33)
        (42 43 44 36)
        (45 46 38 37)
        (47 48 41 40)
        (50 51 44 43)
        (52 53 46 45)
        (56 57 50 49)
        (57 58 51 50)
        (59 60 53 52)
        (60 61 54 53)
        (61 62 55 54)
        (62 63 56 55)
        (63 64 57 56)
        (64 65 58 57)
        );
    }
);

mergePatchPairs
(
);

// ************************************************************************* //

wyldckat April 30, 2015 11:54
Quick answer: The "cyclic" boundary condition requires that the mesh is identical on both boundary surfaces (patches). In other words, imagine you copy-pasted one of the patches and placed it in another place in the mesh, without any morphing changes; you can rotate and translate, but you cannot change the shape of the patch.


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