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bephi July 2, 2012 08:32

snappyHexMesh edges

I really like the idea of sHM and hope to generate some nice meshes but my first attempt were unsuccessful.
Due to the fact that my geometry has no straight edges (only the inlet and outlets are planes) especially the regions at the outlets show bad results. Probably the picture say more than words so maybe someone has an idea what I have done from so far and which setting can deal with those issues. That you very much in advance!

StSchiff July 2, 2012 10:41

Hi bephi,
did you turn the snapping step on?
Looks like you are looking at the castellatedMesh. The first two lines of you snappyHexMeshDict should read:

castellatedMesh true;
snap true;

if it does, how many time folder did snappy create?


bephi July 2, 2012 10:53

Hi Stefanie,

I didn't turn it on yet because I though at the beginning I should provide a nice mesh which is just refined and afterwards I continue with the snapping.

I get one folder for each stage...

So maybe I have to ask a more general question. When my geometry (inlet/outlet) is not parallel to a cartesian plane, is it therefore impossible to have elements normal to these patches? I assume that they will be snapped somehow but can cause problem with the interpolation of the BCs ?!

StSchiff July 3, 2012 02:31

Hi Bephi,
I guess you would have to build the background mesh parallel to your geometry surface. Otherwise the cells get snapped non-parallel to the surface. Or maybe you should try inserting layers at those surfaces. Don't know if that gives you a nice mesh though.

bephi July 3, 2012 02:35

Good morning and thanks for the reply. I thought about that as well but there are several in-/outlet faces and they are located arbitrary in space. Therefore, I assume that sHM might be not the best meshing tool for my application... :(

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