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Old   April 21, 2011, 11:00
Default Problem about mesh
  #1
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Wei Ma
Join Date: Feb 2011
Posts: 14
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Hi guys,
In a case of implementing laplacianFoam, I am gonna generate a simple wedge mesh with:
Code:
convertToMeters 1;

vertices        
(
    (0 0 0)
    (0.01 0 0)
    (0.01 0 0.06)
    (0 0 0.06)
    (0 0.08 0)
    (0.01 0.08 0)
);

blocks          
(
    hex (0 1 2 3 4 5 5 4) (1 80 60) simpleGrading (1 1 1)
);

edges           
(
);

patches         
(
    patch heat_in
    (
       (0 1 5 4)
    )
    patch heat_out
    (
       (2 3 4 5)
    )
    patch wall 
    (
       (0 1 2 3)
       (4 5 5 4)
    )
    empty infi
    (
       (0 3 4 4)
       (1 2 5 5)
    )
);

mergePatchPairs 
(
);
error occurred when I tried to run solver, then I ran checkMesh, it showed:
Code:
Checking geometry...
    Overall domain bounding box (0 0 0) (0.01 0.08 0.06)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (6.47958e-19 1.52937e-18 1.8823e-18) OK.
 ***High aspect ratio cells found, Max aspect ratio: 6.65658e+194, number of cells 4800
  <<Writing 4800 cells with high aspect ratio to set highAspectRatioCells
    Minumum face area = 8.33333e-09. Maximum face area = 1.66667e-05.  Face area magnitudes OK.
    Min volume = 1.66667e-300. Max volume = 2e-300.  Total volume = 9.57333e-297.  Cell volumes OK.
    Mesh non-orthogonality Max: 179.731 average: 157.57
 ***Number of non-orthogonality errors: 9460.
  <<Writing 9460 non-orthogonal faces to set nonOrthoFaces
 ***Error in face pyramids: 28720 faces are incorrectly oriented.
  <<Writing 19260 faces with incorrect orientation to set wrongOrientedFaces
    Max skewness = 1.32376 OK.
Could anybody give a clue about what is going on, and how to fix it?

Thank you for help in advance!!

-Merlin
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Old   April 21, 2011, 13:20
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  #2
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hossein
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Hi Merlin

i m not sure but i think for generation of wedge you must have 2 patches of type wedge and a patch of type symmetryPlane, i dont see them in your blockMeshDict.

i hope i m true.
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Old   April 21, 2011, 13:43
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  #3
ngj
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Niels Gjoel Jacobsen
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ngj will become famous soon enoughngj will become famous soon enough
Hi Merlin

The error in your checkMesh suggest that you have defined an incorrect coordinate system. It should always yield a x-y-z system, where you define x-z-y, see the UserGuide.

I have never used wedge, however, I suspect that changing to the following would help

Code:
(0 1 2 3 4 5 5 4) -> (0 1 5 4 3 2 5 4)
Furthermore remove or comment the patch-definitions. This will put all the patches to default as a start, and you can concentrate on getting the mesh working.

Best regards

Niels
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Old   April 21, 2011, 17:05
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  #4
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Wei Ma
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Quote:
Originally Posted by ngj View Post
Hi Merlin

The error in your checkMesh suggest that you have defined an incorrect coordinate system. It should always yield a x-y-z system, where you define x-z-y, see the UserGuide.

I have never used wedge, however, I suspect that changing to the following would help

Code:
(0 1 2 3 4 5 5 4) -> (0 1 5 4 3 2 5 4)
Furthermore remove or comment the patch-definitions. This will put all the patches to default as a start, and you can concentrate on getting the mesh working.

Best regards

Niels
Hi Niels,

Your suggestion really works !! Appreciate it. now my program is working well.

-Merlin
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