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[ICEM] Strategy for sharp corners

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Old   March 22, 2013, 09:00
Default Strategy for sharp corners
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Rolando Figueiredo
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Hello again,

I've managed to create a relatively satisfactory mesh, but I am struggling with its quality. As you can see in the image bellow, the model contains to problematic corners - very obtuse/acute angles.



You any of you recommend a different way of meshing this in order to improve the quality? Above 0.4 would be OK!

Thank you in advance!
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Old   March 22, 2013, 09:30
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Sijal Ahmed Memon (turboenginner@gmail.com)
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I am not able to see any image ... please attach again
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Old   March 22, 2013, 10:00
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Sorry, here it is!
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Old   March 22, 2013, 10:03
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Sijal Ahmed Memon (turboenginner@gmail.com)
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what is the problem?
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Old   March 22, 2013, 10:10
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The element quality near the outlet and the periodic walls is very low due to the angles, I guess. Do you reckon there's a better way to mesh those corners, or is the low quality something I'll have to accept?
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Old   March 22, 2013, 10:16
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Actually I cannot visualize that area. Can you pin point that area and how much quality do you get?
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Old   March 22, 2013, 10:27
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Here. Basically the geometry itself causes low orthogonality.
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Old   March 22, 2013, 10:30
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How much low? Like how much quality you have, min angle, dihedral angle, orthogonality, max volume change?

Plot with quality check menu and click on bars with low quality and post those pics
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Old   March 22, 2013, 10:47
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Since I've just started dealing with CFD, I have been following the >0.4 Quality index (it's a CFX parameter). Not really sure how much would the max. volume change figure be, though!
I've also been informed to keep angles >18deg.

Thanks a lot for your time!
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File Type: jpg angle.jpg (75.4 KB, 21 views)
File Type: jpg orthogonality.jpg (79.2 KB, 15 views)
File Type: jpg quality.jpg (52.3 KB, 13 views)
File Type: jpg volumechange.jpg (61.8 KB, 11 views)
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Old   March 22, 2013, 10:58
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Quality > 0.3 is good enough.
But maybe you could improve the quality in this area. Can you share .tin and .blk files ?
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Old   March 22, 2013, 11:10
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I can see no problem in mesh. Every things seems ok. What is the maximum Y+?
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Old   March 22, 2013, 11:16
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Not sure, I'll carry out a sensibility analysis probably resulting in a finner mesh (~1.5m elements, perhaps).

Thanks for the replies!
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Old   March 22, 2013, 11:17
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Quote:
Originally Posted by BrolY View Post
Quality > 0.3 is good enough.
But maybe you could improve the quality in this area. Can you share .tin and .blk files ?
I've tried doing it by moving the nodes - no success!
Is there another method you'd suggest? I was advised not to share the files, sorry! --'
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Old   March 22, 2013, 11:25
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Quote:
Originally Posted by RPFigueiredo View Post
I was advised not to share the files, sorry! --'
In fact sharing them will give you good response from forum fellows. You can share privately.

Choice is yours.
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Old   March 22, 2013, 11:45
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OK, If I would get some help with that, I could share the files for both stator and rotor (which looks a bit more messy...).
Can I share them here or should I get your e-mails through PM?
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Old   March 22, 2013, 11:46
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if it is confidential then through pm.
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