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RPFigueiredo March 22, 2013 09:00

Strategy for sharp corners
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!

Far March 22, 2013 09:30

I am not able to see any image ... please attach again

RPFigueiredo March 22, 2013 10:00

1 Attachment(s)
Sorry, here it is!

Far March 22, 2013 10:03

what is the problem?

RPFigueiredo March 22, 2013 10:10

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?

Far March 22, 2013 10:16

Actually I cannot visualize that area. Can you pin point that area and how much quality do you get?

RPFigueiredo March 22, 2013 10:27

1 Attachment(s)
Here. Basically the geometry itself causes low orthogonality.

Far March 22, 2013 10:30

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

RPFigueiredo March 22, 2013 10:47

4 Attachment(s)
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!

BrolY March 22, 2013 10:58

Quality > 0.3 is good enough.
But maybe you could improve the quality in this area. Can you share .tin and .blk files ?

Far March 22, 2013 11:10

I can see no problem in mesh. Every things seems ok. What is the maximum Y+?

RPFigueiredo March 22, 2013 11:16

Not sure, I'll carry out a sensibility analysis probably resulting in a finner mesh (~1.5m elements, perhaps).

Thanks for the replies!

RPFigueiredo March 22, 2013 11:17


Originally Posted by BrolY (Post 415737)
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! --'

Far March 22, 2013 11:25


Originally Posted by RPFigueiredo (Post 415747)
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. :o

RPFigueiredo March 22, 2013 11:45

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?

Far March 22, 2013 11:46

if it is confidential then through pm.

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