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2D axissym mesh problem

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Old   August 7, 2006, 18:02
Default I want to create a 2D axis-sym
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chris book
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I want to create a 2D axis-sym mesh:

I have used the following blockMeshDict
vertices
(
(0 0 0)
(44.956 -1.963 0)
(44.956 1.963 0)
(0 0 90)
(44.956 -1.963 90)
(44.956 1.963 90)
);

blocks
(
hex (0 1 2 0 3 4 5 3) (20 1 20) simpleGrading (1 1 1)
);

edges
(
arc 1 2 (45 0 0)
arc 4 5 (45 0 90)
);

patches
...


But when I run checkMesh, the util complains about highly skewed cells!

--> FOAM Warning :
From function primitiveMesh::checkFaceSkewness(const bool report, labelHashSet* setPtr) const
in file meshes/primitiveMesh/primitiveMeshCheck.C at line 834
Large face skewness detected. Max skewness = 284.634 percent.
This may impair the quality of the result.
40 highly skew faces detected.
Writing 40 skew faces to set skewFaces


What is wrong with my mesh. Is there something what I can do to get rid of the bad skewness???
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Old   September 15, 2006, 08:40
Default Can nobody comment my mesh pro
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Can nobody comment my mesh problem?
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Old   September 15, 2006, 12:01
Default checkMesh says that there is s
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Mattijs Janssens
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checkMesh says that there is skewness for boundary faces. If you check you'll see that all your wedge faces are skew, i.e. the face centre is not the normal projection of the cell centre. Make the skew angle larger and you'll see where the error comes from.
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Old   September 15, 2006, 12:16
Default Thanks Mattijs, so the prob
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Thanks Mattijs,

so the problem with highly skewed cells is unavoidable with a "wedge" geomertry right? Please correct me if I am wrong.

If not, how to do a better wedge mesh?
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Old   September 17, 2006, 13:06
Default Ok the faces which checkMesh c
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Ok the faces which checkMesh complains belong to cells which are aligned along the axis of my wedge.

So I was wondering if someone is able to tell me how to create a wedge without skewed faces? See my first message this is the way I am creating the wedge at the moment.
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Old   September 17, 2006, 13:32
Default I suspect what bothers you are
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Hrvoje Jasak
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I suspect what bothers you are the faces on the front and back surface of the wedge - you can safely ignore the message there. If you wish, you can remove zero-area faces on the axis itself, simply be creating only one set of axis points and using duplicates in block definition.

Enjoy,

Hrv
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