Collapsing layers
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Hello,
I created a 2D mesh using snappyHexMesh. My problem is that the added layers collapse at the end of the layer surface, see attached picture in the lower right corner. Is there any possiblity to avoid collapsing layers? Here's my snappyHexMeshDict: Code:
/*--------------------------------*- C++ -*----------------------------------*\ Thanks, Michael [IMG]file:///home/itsnas/haemmerl/OpenFOAM/haemmerl-2.1.x/run/testcase/AGTURBO/WM_LES/layers.png[/IMG][IMG]file:///home/itsnas/haemmerl/OpenFOAM/haemmerl-2.1.x/run/testcase/AGTURBO/WM_LES/layers.png[/IMG] |
Hi Michael,
Here is my suggestion: 1) Run snappyHexMesh steps castellation and snap only Code:
castellatedMesh true; snap true; addLayers false; 2) with the changeDictionary utility, change your lower patch from "patch" or "wall" to "empty" 3) Run snappyHexMesh step layers only Code:
castellatedMesh false; snap false; addLayers true; 4) with the changeDictionary utility, change your lower patch from "empty" to "patch" or "wall" This worked well for me as long as I ran in serial, I got the idea from this thread If you get a way to have it to work in parallel meshing, I'd be interested :) Good luck! Eloïse |
2 Attachment(s)
Thanks for your reply!
The layers look great now! But the boundary that I've changed to empty now is not plane anymore but deformed. The first image shows the deformed surface, image 2 shows how it was before. Any ideas how to fix this? |
Hi Michael,
I also observed some deformations with this process and, just as you, I'm not fully satisfied with the resulting mesh. But I haven't made further progress on that case yet. If someone has a solution for it, I'd be glad to read about it! Regards, Eloïse |
Hi,
to avoid deformation of the mesh first you can try to run the castellated, snap and addLayers all separately. In snappyHexMesh there is also the entry nSmoothPatch in snapControls, which is the number of pre-smoothing iteration, you can try to set it equal to zero if you have sharp edges and you want to maintain it. Regarding the collapsing of layers, the entry featureAngle has a key role, if you set it 180° you should obtain no layers collapsed, but I have seen that you have already used this value. I hope these advice help you. Chiara |
You can also take a look to point 2 in this page:
http://openfoamwiki.net/index.php/SnappyHexMesh --> A Comprehensive Tour of snappyHexMesh - 7th OpenFOAM Workshop (25 June 2012). it helps me a lot to understand how sHM works. Regards, Chiara |
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