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-   -   expansion factor in Ansa (http://www.cfd-online.com/Forums/ansa/120948-expansion-factor-ansa.html)

wjy-c July 17, 2013 22:23

expansion factor in Ansa
 
hi, i'm trying to simulate a oil splash in a gearbox due to the gear rotating. my the solve process could not continue, and i checked the output file. i noticed that the mesh statistic point out that the grid's expansion factor in some domain is "!", which means unacceptable.

in order to avoild this problem. when i generating the volume, i used the "tetra FEM". but the expansion problem is still there when i calculating.

i find out that there is no such quality criteria to check the expansion problem, and i do not know why there is an expansion problem.

would anyone have experience please help me? thank you!

vangelis July 27, 2013 05:41

Hi There

Which ANSA version are you using?
Here are some suggestions

-Use MESHV>TETRA RAPID instead of TetraFEM it is much faster
-You should check for example Solid Fluent Skewness for 0.9 (an area with very abrupt expansion should also be bad in skewness too
-You can also check for Solid Growth Rate say 5

In any case the problem usually comes from bad quality shell mesh
Before MESHV check that you shell mesh has Fluent Skew<0.7 for example

Hope this helps

Vangelis


Quote:

Originally Posted by wjy-c (Post 440435)
hi, i'm trying to simulate a oil splash in a gearbox due to the gear rotating. my the solve process could not continue, and i checked the output file. i noticed that the mesh statistic point out that the grid's expansion factor in some domain is "!", which means unacceptable.

in order to avoild this problem. when i generating the volume, i used the "tetra FEM". but the expansion problem is still there when i calculating.

i find out that there is no such quality criteria to check the expansion problem, and i do not know why there is an expansion problem.

would anyone have experience please help me? thank you!



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