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-   -   mesh quality problems: maximum skewness larger than 0.98 (http://www.cfd-online.com/Forums/fluent/96605-mesh-quality-problems-maximum-skewness-larger-than-0-98-a.html)

cth_yao January 26, 2012 19:24

mesh quality problems: maximum skewness larger than 0.98
 
Hi there. I am simulating a numerical wave tank with a chamber in it. I build the mesh with DM meshing, but when I run it in FLUENT, there is a warning

maximum cell skewness exceed 0.98

what is the problem that causes the warning?

besides this warning, there are two other things, the maximum cell squish is 0.9655 and the maximum aspect ratio is 256.198
does it mean the mesh quality is low?

how can I deal with these problems?

thanks!

-mAx- January 27, 2012 06:03

check your mesh quality, display worst elements, and fix problems.
You need to go back on your mesher for that

mali28 January 27, 2012 06:05

Quote:

Originally Posted by cth_yao (Post 341396)
Hi there. I am simulating a numerical wave tank with a chamber in it. I build the mesh with DM meshing, but when I run it in FLUENT, there is a warning

maximum cell skewness exceed 0.98

what is the problem that causes the warning?

besides this warning, there are two other things, the maximum cell squish is 0.9655 and the maximum aspect ratio is 256.198
does it mean the mesh quality is low?

how can I deal with these problems?

thanks!


Mesh skewness is high if you are using unstructured mesh. But generally, it should be less than 0.85 for tetrahedral cells.
Even a few cells with high skewness can cause trouble in convergence and may even lead to divergence.

shaoda169 January 27, 2012 06:50

Quote:

Originally Posted by -mAx- (Post 341462)
check your mesh quality, display worst elements, and fix problems.
You need to go back on your mesher for that

Yes, you r right. Actually it is very important to pay efforts to generate 'good' mesh before iteration in FLUENT!

rgd May 19, 2016 10:59

Quote:

Originally Posted by mali28 (Post 341463)
Mesh skewness is high if you are using unstructured mesh. But generally, it should be less than 0.85 for tetrahedral cells.
Even a few cells with high skewness can cause trouble in convergence and may even lead to divergence.

Do you have the rule of thumb for maximum skewness for all types of mesh??


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