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-   -   snappyHexMesh and refineWallLayer (http://www.cfd-online.com/Forums/openfoam-meshing-snappyhexmesh/119620-snappyhexmesh-refinewalllayer.html)

Claudio June 20, 2013 14:36

snappyHexMesh and refineWallLayer
 
5 Attachment(s)
Hi All,

I'm trying to get a decent looking grid for the Wigley Hull tutorial, but have not been successful so far.
First thing I tried was to use snappyHexMesh to create multiple layers near the hull surface, and through a lot of trial and error I got to the point where the layers looked very good in certain parts but still failed in others. I tried my best to explain what happens in this post.

I then went on to try a different way, which was to create one single thick layer to be subsequently divided into multiple layer using the refineWallLayer routine. Even creating a single layer was not completely successful (as the attached pictures show), since there is a small patch near the bow where the layer does not grow. It's a bit of a mistery since the geometry is symmetric front to back and side to side, which means that except for orientation each "quarter" of the geometry is the same. Still for 3 of them it works beautifully, but not for one.
If I run checkMesh after creating a single layer, I get that 35 faces have high skew (max is 8.78, see log.checkMesh_SL).
I then run refineWallLayer a few times with a ratio of about 0.7, and run checkMesh again. Now the mesh fails 4 checks (2 open cells, 3479 non-orthogonal faces, 5 incorrectly oriented faces, 1741 highly skewed faces).

Is there a way to prevent this? Maybe another application to run between each instance of refineWallLayer that would smooth the mesh out? I tried running sHM with only addLayer true, but nSurfaceLayers 0, to try to use the smoothing options, but it did not work.

Any help for creating a good BL mesh will be greatly appreciated.

Claudio


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