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-   -   snappyHexMesh and cyclic boundaries (http://www.cfd-online.com/Forums/openfoam-meshing/127230-snappyhexmesh-cyclic-boundaries.html)

Ruli December 6, 2013 09:55

snappyHexMesh and cyclic boundaries
 
2 Attachment(s)
Dear Foamers,
again I ask for help. I am working on the simulation of a rotating wind turbine rotor blade. With blockMesh I create a 120 'wedge' which later shall contain 1 rotor blade (see figure 1). Finally I figured out how to create the blockMesh blocks in a way, that snappy works properly, see here:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  2.2.2                                |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version    2.0;
    format      ascii;
    class      dictionary;
    object      blockMeshDict;
}

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

#include        "include/vertices"

convertToMeters 1;

vertices
(
    ($x_up_up        $y_in_out    $z_in_out_pos)
    ($x_up        $y_in_out    $z_in_out_pos)
    ($x_down        $y_in_out    $z_in_out_pos)
    ($x_down_down    $y_in_out    $z_in_out_pos)
    ($x_up_up        $y_mid_out    $z_mid_out_pos)
    ($x_up        $y_mid_out    $z_mid_out_pos)
    ($x_down        $y_mid_out    $z_mid_out_pos)
    ($x_down_down    $y_mid_out    $z_mid_out_pos)
    ($x_up_up        $y_out_out    $z_out_out_pos)
    ($x_up        $y_out_out    $z_out_out_pos)
    ($x_down        $y_out_out    $z_out_out_pos)
    ($x_down_down    $y_out_out    $z_out_out_pos)

    ($x_up_up        $y_in_in    $z_in_in_pos)
    ($x_up        $y_in_in    $z_in_in_pos)
    ($x_down        $y_in_in    $z_in_in_pos)
    ($x_down_down    $y_in_in    $z_in_in_pos)
    ($x_up_up        $y_mid_in    $z_mid_in_pos)
    ($x_up        $y_mid_in    $z_mid_in_pos)
    ($x_down        $y_mid_in    $z_mid_in_pos)
    ($x_down_down    $y_mid_in    $z_mid_in_pos)
    ($x_up_up        $y_out_in    $z_out_in_pos)
    ($x_up        $y_out_in    $z_out_in_pos)
    ($x_down        $y_out_in    $z_out_in_pos)
    ($x_down_down    $y_out_in    $z_out_in_pos)

    ($x_up_up        $y_in_in    $z_in_in_neg)
    ($x_up        $y_in_in    $z_in_in_neg)
    ($x_down        $y_in_in    $z_in_in_neg)
    ($x_down_down    $y_in_in    $z_in_in_neg)
    ($x_up_up        $y_mid_in    $z_mid_in_neg)
    ($x_up        $y_mid_in    $z_mid_in_neg)
    ($x_down        $y_mid_in    $z_mid_in_neg)
    ($x_down_down    $y_mid_in    $z_mid_in_neg)
    ($x_up_up        $y_out_in    $z_out_in_neg)
    ($x_up        $y_out_in    $z_out_in_neg)
    ($x_down        $y_out_in    $z_out_in_neg)
    ($x_down_down    $y_out_in    $z_out_in_neg)

    ($x_up_up        $y_in_out    $z_in_out_neg)
    ($x_up        $y_in_out    $z_in_out_neg)
    ($x_down        $y_in_out    $z_in_out_neg)
    ($x_down_down    $y_in_out    $z_in_out_neg)
    ($x_up_up        $y_mid_out    $z_mid_out_neg)
    ($x_up        $y_mid_out    $z_mid_out_neg)
    ($x_down        $y_mid_out    $z_mid_out_neg)
    ($x_down_down    $y_mid_out    $z_mid_out_neg)
    ($x_up_up        $y_out_out    $z_out_out_neg)
    ($x_up        $y_out_out    $z_out_out_neg)
    ($x_down        $y_out_out    $z_out_out_neg)
    ($x_down_down    $y_out_out    $z_out_out_neg)
);

blocks
(
    hex (12 13 17 16 0 1 5 4) ($N_x_up $N_y_c $N_z_pos) simpleGrading ($R_x_up 1 $R_z_pos)
    hex (24 25 29 28 12 13 17 16) ($N_x_up $N_y_c $N_z_c) simpleGrading ($R_x_up 1 1)
    hex (36 37 41 40 24 25 29 28) ($N_x_up $N_y_c $N_z_neg) simpleGrading ($R_x_up 1 $R_z_neg)

    hex (16 17 21 20 4 5 9 8) ($N_x_up $N_y $N_z_pos) simpleGrading ($R_x_up $R_y $R_z_pos)
    hex (28 29 33 32 16 17 21 20) ($N_x_up $N_y $N_z_c) simpleGrading ($R_x_up $R_y 1)
    hex (40 41 45 44 28 29 33 32) ($N_x_up $N_y $N_z_neg) simpleGrading ($R_x_up $R_y $R_z_neg)

    hex (13 14 18 17 1 2 6 5) ($N_x_c $N_y_c $N_z_pos) simpleGrading (1 1 $R_z_pos)
    hex (25 26 30 29 13 14 18 17) ($N_x_c $N_y_c $N_z_c) simpleGrading (1 1 1)
    hex (37 38 42 41 25 26 30 29) ($N_x_c $N_y_c $N_z_neg) simpleGrading (1 1 $R_z_neg)

    hex (17 18 22 21 5 6 10 9) ($N_x_c $N_y $N_z_pos) simpleGrading (1 $R_y $R_z_pos)
    hex (29 30 34 33 17 18 22 21) ($N_x_c $N_y $N_z_c) simpleGrading (1 $R_y 1)
    hex (41 42 46 45 29 30 34 33) ($N_x_c $N_y $N_z_neg) simpleGrading (1 $R_y $R_z_neg)

    hex (14 15 19 18 2 3 7 6) ($N_x_down $N_y_c $N_z_pos) simpleGrading ($R_x_down 1 $R_z_pos)
    hex (26 27 31 30 14 15 19 18) ($N_x_down $N_y_c $N_z_c) simpleGrading ($R_x_down 1 1)
    hex (38 39 43 42 26 27 31 30) ($N_x_down $N_y_c $N_z_neg) simpleGrading ($R_x_down 1 $R_z_neg)

    hex (18 19 23 22 6 7 11 10) ($N_x_down $N_y $N_z_pos) simpleGrading ($R_x_down $R_y $R_z_pos)
    hex (30 31 35 34 18 19 23 22) ($N_x_down $N_y $N_z_c) simpleGrading ($R_x_down $R_y 1)
    hex (42 43 47 46 30 31 35 34) ($N_x_down $N_y $N_z_neg) simpleGrading ($R_x_down $R_y $R_z_neg)
);

edges
(
    arc 0 12  ($x_up_up    $y_arc_in    $z_arc_in_pos)
    arc 12 24 ($x_up_up    $y_arc_in_c    $z_arc_in_c)
    arc 24 36 ($x_up_up    $y_arc_in    $z_arc_in_neg)

    arc 1 13  ($x_up        $y_arc_in    $z_arc_in_pos)
    arc 13 25 ($x_up        $y_arc_in_c    $z_arc_in_c)
    arc 25 37 ($x_up        $y_arc_in    $z_arc_in_neg)

    arc 2 14  ($x_down        $y_arc_in    $z_arc_in_pos)
    arc 14 26 ($x_down        $y_arc_in_c    $z_arc_in_c)
    arc 26 38 ($x_down        $y_arc_in    $z_arc_in_neg)

    arc 3 15  ($x_down_down    $y_arc_in    $z_arc_in_pos)
    arc 15 27 ($x_down_down    $y_arc_in_c    $z_arc_in_c)
    arc 27 39 ($x_down_down    $y_arc_in    $z_arc_in_neg)

    arc 4 16  ($x_up_up    $y_arc_mid    $z_arc_mid_pos)
    arc 16 28 ($x_up_up    $y_arc_mid_c    $z_arc_mid_c)
    arc 28 40 ($x_up_up    $y_arc_mid    $z_arc_mid_neg)

    arc 5 17  ($x_up        $y_arc_mid    $z_arc_mid_pos)
    arc 17 29 ($x_up        $y_arc_mid_c    $z_arc_mid_c)
    arc 29 41 ($x_up        $y_arc_mid    $z_arc_mid_neg)

    arc 6 18  ($x_down        $y_arc_mid    $z_arc_mid_pos)
    arc 18 30 ($x_down        $y_arc_mid_c    $z_arc_mid_c)
    arc 30 42 ($x_down        $y_arc_mid    $z_arc_mid_neg)

    arc 7 19  ($x_down_down    $y_arc_mid    $z_arc_mid_pos)
    arc 19 31 ($x_down_down    $y_arc_mid_c    $z_arc_mid_c)
    arc 31 43 ($x_down_down    $y_arc_mid    $z_arc_mid_neg)

    arc 8 20  ($x_up_up    $y_arc_out    $z_arc_out_pos)
    arc 20 32 ($x_up_up    $y_arc_out_c    $z_arc_out_c)
    arc 32 44 ($x_up_up    $y_arc_out    $z_arc_out_neg)

    arc 9 21  ($x_up        $y_arc_out    $z_arc_out_pos)
    arc 21 33 ($x_up        $y_arc_out_c    $z_arc_out_c)
    arc 33 45 ($x_up        $y_arc_out    $z_arc_out_neg)

    arc 10 22 ($x_down        $y_arc_out    $z_arc_out_pos)
    arc 22 34 ($x_down        $y_arc_out_c    $z_arc_out_c)
    arc 34 46 ($x_down        $y_arc_out    $z_arc_out_neg)

    arc 11 23 ($x_down_down    $y_arc_out    $z_arc_out_pos)
    arc 23 35 ($x_down_down    $y_arc_out_c    $z_arc_out_c)
    arc 35 47 ($x_down_down    $y_arc_out    $z_arc_out_neg)

    polyLine 24 28 (
    ($x_up_up $y_TE_in $z_TE_in)
    ($x_up_up $y_TE_mid $z_TE_mid)
    ($x_up_up $y_TE_out $z_TE_out)
              )
    polyLine 25 29 (
    ($x_up $y_TE_in $z_TE_in)
    ($x_up $y_TE_mid $z_TE_mid)
    ($x_up $y_TE_out $z_TE_out)
              )
    polyLine 26 30 (
    ($x_down $y_TE_in $z_TE_in)
    ($x_down $y_TE_mid $z_TE_mid)
    ($x_down $y_TE_out $z_TE_out)
              )
    polyLine 27 31 (
    ($x_down_down $y_TE_in $z_TE_in)
    ($x_down_down $y_TE_mid $z_TE_mid)
    ($x_down_down $y_TE_out $z_TE_out)
              )

);

boundary
(
    inlet
    {
        type patch;
        faces
        (
            (4 16 12 0)
            (16 28 24 12)
            (28 40 36 24)
            (8 20 16 4)
            (20 32 28 16)
            (32 44 40 28)
        );
    }
    outlet
    {
        type patch;
        faces
        (
            (7 3 15 19)
            (19 15 27 31)
            (31 27 39 43)
            (11 7 19 23)
            (23 19 31 35)
            (35 31 43 47)
        );
    }
    innerWall
    {
        type wall;
        faces
        (
            (0 12 13 1)
            (12 24 25 13)
            (24 36 37 25)
            (1 13 14 2)
            (13 25 26 14)
            (25 37 38 26)
            (2 14 15 3)
            (14 26 27 15)
            (26 38 39 27)
        );
    }
    outerWall
    {
        type patch;
        faces
        (
            (8 9 21 20)
            (20 21 33 32)
            (32 33 45 44)
            (9 10 22 21)
            (21 22 34 33)
            (33 34 46 45)
            (10 11 23 22)
            (22 23 35 34)
            (34 35 47 46)
        );
    }
    /*rightWall
    {
        type patch;
    faces
        (
            (8 4 5 9)
            (4 0 1 5)
            (9 5 6 10)
            (5 1 2 6)
            (10 6 7 11)
            (6 2 3 7)
        );
    }
    leftWall
    {
        type patch;
    faces
        (
            (44 45 41 40)
            (40 41 37 36)
            (45 46 42 41)
            (41 42 38 37)
            (46 47 43 42)
            (42 43 39 38)
        );
    }*/
    rightWall
    {
        type cyclic;
        neighbourPatch leftWall;
    faces
        (
            (8 4 5 9)
            (4 0 1 5)
            (9 5 6 10)
            (5 1 2 6)
            (10 6 7 11)
            (6 2 3 7)
        );
    }
    leftWall
    {
        type cyclic;
        neighbourPatch rightWall;
    faces
        (
            (44 45 41 40)
            (40 41 37 36)
            (45 46 42 41)
            (41 42 38 37)
            (46 47 43 42)
            (42 43 39 38)
        );
    }
);

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

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  2.2.2                                |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/

// +++ Vertex coodinates
//x-direction
x_up_up            -4;
x_up                -0.04;
x_down_down            7;
x_down                0.03;
//y-direction
y_in_out            0.03457;
y_mid_out            0.55957;
y_out_out            2.50000;
y_in_in                0.05988;
y_mid_in            1.10988;
y_out_in            4.33013;
//z-direction
z_in_out_pos        0.05988;
z_in_out_neg        -0.05988;
z_mid_out_pos        0.96921;
z_mid_out_neg        -0.96921;
z_out_out_pos        4.33013;
z_out_out_neg        -4.33013;
z_in_in_pos          0.03457;
z_in_in_neg          -0.03457;
z_mid_in_pos        0.03457;
z_mid_in_neg        -0.03457;
z_out_in_pos        2.50000;
z_out_in_neg        -2.50000;

// +++ Block grading parameters
//x-direction
N_x_c                20;
N_x_up                65;
N_x_down            95;
R_x_up                0.01334;
R_x_down            95.78231;
//y-direction
N_y_c                300;
N_y                65;
R_y                73.47398;
//z-direction
N_z_c                10;
N_z_pos                5;
N_z_neg                5;
R_z_pos                1.12151;
R_z_neg                0.89166;

// +++ Arc vertices
//y-coordinates
y_arc_in_c        0.06914;
y_arc_mid_c        1.11914;
y_arc_out_c        5.00000;
y_arc_in        0.04889;
y_arc_mid        0.79135;
y_arc_out        3.53553;
//z-coordinates
z_arc_in_c        0.00000;
z_arc_mid_c        0.00000;
z_arc_out_c        0.00000;
z_arc_in_pos        0.04889;
z_arc_in_neg        -0.04889;
z_arc_mid_pos        0.79135;
z_arc_mid_neg        -0.79135;
z_arc_out_pos        3.53553;
z_arc_out_neg        -3.53553;

// +++ TE vertices
y_TE_in            0.167;
y_TE_mid        0.333;
y_TE_out        0.5;

z_TE_in            -0.07;
z_TE_mid        -0.07;
z_TE_out        -0.03457;


#inputMode          merge

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

But here is my current problem: If I set the faces on the wedge sites as cyclic, snappy does work very slowly (even in non-parallel mode) and brings the following 'error' messages ("Cannot find point ..."):

Code:

/*---------------------------------------------------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  2.2.2                                |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
Build  : 2.2.2-9240f8b967db
Exec  : snappyHexMesh
Date  : Dec 06 2013
Time  : 14:33:26
Host  : "julian-Pc"
PID    : 3959
Case  : /home/julian/OpenFOAM/julian-2.2.2/run/mesh_MRF_20131206
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

Read mesh in = 1.05 s

Overall mesh bounding box  : (-4 0.03457 -4.33013) (7 5 4.33013)
Relative tolerance        : 1e-06
Absolute matching distance : 1.48545e-05

Reading refinement surfaces.
Read refinement surfaces in = 0.58 s

Reading refinement shells.
Read refinement shells in = 0 s

Setting refinement level of surface to be consistent with shells.
Checked shell refinement in = 0 s

Reading features.
Read features in = 0 s


Determining initial surface intersections
-----------------------------------------

Edge intersection testing:
    Number of edges            : 3952900
    Number of edges to retest  : 3952900
    Number of intersected edges : 5663
Calculated surface intersections in = 4.89 s

Initial mesh : cells:1314000  faces:3952900  points:1324920
Cells per refinement level:
    0    1314000

Adding patches for surface regions
----------------------------------

Patch    Type    Region
-----    ----    ------
rotor:

6    wall    rotor_OBJECT

Added patches in = 0.09 s

Selecting decompositionMethod none

Refinement phase
----------------

Found point (0 4 0) in cell 607411 on processor 0

Surface refinement iteration 0
------------------------------

Marked for refinement due to surface intersection          : 7630 cells.
Marked for refinement due to curvature/regions            : 0 cells.
Determined cells to refine in = 1.16 s
Selected for refinement : 7630 cells (out of 1314000)
Cannot find point in pts1 matching point 28325 coord:(0.00025 0.035445 -0.0613955) in pts0 when using tolerance 2.47488e-07
Searching started from:0 in pts1
    Compared coord: (0.00025 0.0354477 -0.061394) at index 0 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 28025 coord:(-0.00325 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:0 in pts1
    Compared coord: (0.00025 0.0354477 -0.061394) at index 0 with difference to point 0.0035
    Compared coord: (-0.00325 0.0354477 -0.061394) at index 1 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 28625 coord:(0.00375 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:1 in pts1
    Compared coord: (-0.00325 0.0354477 -0.061394) at index 1 with difference to point 0.007
    Compared coord: (0.00375 0.0354477 -0.061394) at index 2 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 27725 coord:(-0.00675 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:2 in pts1
    Compared coord: (0.00375 0.0354477 -0.061394) at index 2 with difference to point 0.0105
    Compared coord: (-0.00675 0.0354477 -0.061394) at index 3 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 28925 coord:(0.00725 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:3 in pts1
    Compared coord: (-0.00675 0.0354477 -0.061394) at index 3 with difference to point 0.014
    Compared coord: (0.00725 0.0354477 -0.061394) at index 4 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 27425 coord:(-0.01025 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:4 in pts1
    Compared coord: (0.00725 0.0354477 -0.061394) at index 4 with difference to point 0.0175
    Compared coord: (-0.01025 0.0354477 -0.061394) at index 5 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 29225 coord:(0.01075 0.035445 -0.0613955) in pts0 when using tolerance 2.47488e-07
Searching started from:5 in pts1
    Compared coord: (-0.01025 0.0354477 -0.061394) at index 5 with difference to point 0.021
    Compared coord: (0.01075 0.0354477 -0.061394) at index 6 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 27125 coord:(-0.01375 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:6 in pts1
    Compared coord: (0.01075 0.0354477 -0.061394) at index 6 with difference to point 0.0245
    Compared coord: (-0.01375 0.0354477 -0.061394) at index 7 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 29525 coord:(0.01425 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:7 in pts1
    Compared coord: (-0.01375 0.0354477 -0.061394) at index 7 with difference to point 0.028
    Compared coord: (0.01425 0.0354477 -0.061394) at index 8 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 26825 coord:(-0.01725 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:8 in pts1
    Compared coord: (0.01425 0.0354477 -0.061394) at index 8 with difference to point 0.0315
    Compared coord: (-0.01725 0.0354477 -0.061394) at index 9 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 29825 coord:(0.01775 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:9 in pts1
    Compared coord: (-0.01725 0.0354477 -0.061394) at index 9 with difference to point 0.035
    Compared coord: (0.01775 0.0354477 -0.061394) at index 10 with difference to point 3.07029e-06
Cannot find point in pts1 matching point 26525 coord:(-0.02075 0.035445 -0.0613956) in pts0 when using tolerance 2.47488e-07
Searching started from:10 in pts1
    Compared coord: (0.01775 0.0354477 -0.061394) at index 10 with difference to point 0.0385

AND SO ON...

These errors snappy doesn`t create, when I set the side faces as simple patches (see blockMesh comment). I already read a lot of threads on the forum, but haven`t found the right tip yet. I already checked, if snappy is working on the cyclic patches and changing face matching, but they are not changed by snappy.

Does anyone have a tip how to handle this? Thanks!

Best regards
Julian

Artur December 8, 2013 16:53

Hi,

It's not obvious to me why snappy yields this error in your case. I suggest that you run "checkMesh -allGeometry" on your block mesh to see if everything is indeed in order. If it is then one way to get around the problem would be to create the mesh with other patch types and then use "createPatch -overwrite" and "topoSet" to create the cyclic boundaries afterwards. See the incompressible/pimpleDyMFoam/propeller tutorial as to how it can be done.

Cheers,

A

Ruli December 9, 2013 07:51

1 Attachment(s)
Dear Artur,
thanks for your reply.
This is the outcome from checkMesh -allGeometry -allTopology after running blockMesh with cyclic patches activated:

Code:

Create time

Create polyMesh for time = 0

Enabling all geometry checks.

Time = 0

Mesh stats
    points:          1356957
    faces:            3919600
    internal faces:  3770000
    cells:            1281600
    faces per cell:  6
    boundary patches: 6
    point zones:      0
    face zones:      0
    cell zones:      0

Overall number of cells of each type:
    hexahedra:    1281600
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:    0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
    Patch              Faces    Points  Surface topology                  Bounding box
    inlet              7120    7497    ok (non-closed singly connected)  (-4 0.03457 -4.33013) (-4 5 4.33013)
    outlet              7120    7497    ok (non-closed singly connected)  (7 0.03457 -4.33013) (7 5 4.33013)
    innerWall          3600    3801    ok (non-closed singly connected)  (-4 0.03457 -0.05988) (7 0.06914 0.05988)
    outerWall          3600    3801    ok (non-closed singly connected)  (-4 2.5 -4.33013) (7 5 4.33013)
    rightWall          64080    64617    ok (non-closed singly connected)  (-4 0.03457 0.05988) (7 2.5 4.33013)
    leftWall            64080    64617    ok (non-closed singly connected)  (-4 0.03457 -4.33013) (7 2.5 -0.05988)

Checking geometry...
    Overall domain bounding box (-4 0.03457 -4.33013) (7 5 4.33013)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (5.21284e-15 -1.33613e-13 3.22619e-14) OK.
    Max cell openness = 2.93221e-15 OK.
    Max aspect ratio = 132.092 OK.
    Minimum face area = 1.15788e-05. Maximum face area = 0.184686.  Face area magnitudes OK.
    Min volume = 6.90037e-08. Max volume = 0.0466731.  Total volume = 287.397.  Cell volumes OK.
    Mesh non-orthogonality Max: 41.6624 average: 9.46642
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 0.29358 OK.
    Coupled point location match (average 3.61322e-06) OK.
    Face tets OK.
    Min/max edge length = 0.00332535 0.55376 OK.
    All angles in faces OK.
    Face flatness (1 = flat, 0 = butterfly) : average = 1  min = 1
    All face flatness OK.
    Cell determinant (wellposedness) : minimum: 6.52518e-06 average: 1.23701
 ***Cells with small determinant (< 0.001) found, number of cells: 52482
  <<Writing 52482 under-determined cells to set underdeterminedCells
    Concave cell check OK.

Failed 1 mesh checks.

End

As it seems those cells with hight aspect ratios because of grading are underdetermined (see attached figure). What does this exactly mean?

Also I found this thread, where the error "cannot find points in pts1" is asked about:

http://www.cfd-online.com/Forums/ope...er-errors.html

Does anyone have an answer on that topic? It would help me understanding the cause of the error I get when I run snappy.

Looking at the snappy error posted earlier, I noticed, that only the x-coordinates of the tested points (which points are they and what are they tested for???) are causing the mismatching error. Any thoughts on that?

Some other thoughts and actions of mine:
- increasing write precision in controlDict to 10 did not help.
- Do I somehow have to define, that the cyclic patches (which should have exactly the same sizes) are rotated towards each other? Or does blockMesh recognize it on itself?

Thanks and best regards
Julian


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