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[ICEM] High Skewness

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Old   June 22, 2013, 13:04
Default High Skewness
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mohamed khedr emam
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Dear experts,
My Geometry (old case () is a single blade inside a big 120o enclosure sector , after long period i'm stuck with T-Grid skewness problem around the blade surface which appear strongly in Fleunt (after send my file from ICEM). The ICEM T-Grid skewness is high but quality and skewness are good.
I'm using Tetra, unstructured and Robust (octree) meshing techniques, I need a recommended ways to improve T-Grid skewness in ICEM (not Fluent).
Note: I noted that if the total height of blade prism is large, T-Grid skewness will be good but unfortunately in my case the first layer is very small (4e-5) due to y+ condition
image1: prsim
image2: High T.Grid Skewness elements on blade

Thanks in advance
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Old   June 22, 2013, 16:11
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Sijal Ahmed Memon (turboenginner@gmail.com)
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Where this problem occurs?
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Old   June 22, 2013, 16:31
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Hi Far
Quote:
Originally Posted by Far View Post
Where this problem occurs?
At blade surface seems to be between prism and blade surface mesh , here is the file http://www.4shared.com/rar/eJGwRtle/email.html
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Old   June 23, 2013, 22:30
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Any recommendation please
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Old   June 24, 2013, 19:45
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Old   June 28, 2013, 03:01
Default Dealing with sharp trailing edge
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Hi mate,
I suggest make these changes in order to have higher quality mesh:
First as seen in the picture, shell mesh quality is of low quality. As said, garbage in, garbage out. Try improve quality higher than 0.5 by splitting and recreating cells at those areas.
Then run delaunay to have volume mesh.
I ran these two steps and my delaunay mesh quality was more than 0.4.
Next step is to grow prism. Prism meshing is somehow try and error process.
Try these methods:
Make max prism angle 180,
active/inactive Auto Reduction (in Advanced Prism Options)
try floating height by not setting initial height and total height.

The candidate area of bad quality prism is sharp side of airfoil. Try filleting that area with CAD software.

You can try Mulitizone Blocking, which would give high quality quad shell mesh in all of surfaces but one. (Blade Tip)

Beside these, you may have higher prism quality with TGrid, but because of periodic boundaries (i think) you can not export your mesh to TGrid.
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