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Old   February 10, 2013, 15:48
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Jamal Foroozesh
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Hi Dear Friends
I strongly need your help
I have a geometry that is stirred tank. I want to mesh periodic geometry. but I dont know how should I start? Please give your suggestions.
I attached 4 pictures of my problem: 2 pictures are periodic domain that I want to mesh that.

Thank you so much
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File Type: jpg 2.JPG (21.4 KB, 16 views)
File Type: jpg 3.JPG (30.8 KB, 19 views)
File Type: jpg 4.JPG (13.3 KB, 15 views)
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Old   February 11, 2013, 03:40
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http://aerojet.engr.ucdavis.edu/gamb...e/mg04.htm#777
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Old   February 11, 2013, 06:14
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Quote:
Originally Posted by -mAx- View Post
Dear Max
Thank you so much for reply
I can specify zone types but I cant mesh geometry. please help me about meshing strategy.
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Old   February 11, 2013, 06:20
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and why can't you mesh your geometry?
Can you point out the warning or errors you got?
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Old   February 11, 2013, 06:32
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Quote:
Originally Posted by -mAx- View Post
and why can't you mesh your geometry?
Can you point out the warning or errors you got?
I can mesh that but mesh quality is low. I do auto mesh(gambit default mesh) by tet/hybrid/Tgrid in inner zone and hex/wedge/cooper in outer zone.
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Old   February 11, 2013, 07:46
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max skewness about 0.75 is good, limit is 0.9-0.95
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Old   February 11, 2013, 13:08
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Quote:
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max skewness about 0.75 is good, limit is 0.9-0.95
Thanks in advance
But answers is wrong and I know this is due to the bad quality of mesh.
I've already got the correct answers by Another type of impeller by the same parameters in fluent. Its solution in each time step(10^-3) after every 30 iterations would converge but in this case the solution is converge after 80 iterations in each time step(time step is 10^-6).
I attached 2 pictures of previous problem.

Best Regards
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Old   February 12, 2013, 02:27
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and what gives you a check Mesh?
But for sure your skewness is not guilty
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Old   February 12, 2013, 06:08
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Quote:
Originally Posted by -mAx- View Post
and what gives you a check Mesh?
But for sure your skewness is not guilty
Check mesh no problem and its OK
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Old   February 12, 2013, 06:11
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Then you don't have problem with mesh.
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Old   February 12, 2013, 06:17
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Quote:
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Then you don't have problem with mesh.
But when mesh quality is low, solution takes too much time. I know that to solve this problem, mesh quality must be high.

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Old   February 12, 2013, 06:28
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skewness = 0 means perfekt
skewness = 1 means degenerate

....
http://aerojet.engr.ucdavis.edu/gambithelp/html/users_guide/ug0304.htm#gc_exmesh
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Old   February 12, 2013, 07:18
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Quote:
Originally Posted by -mAx- View Post
skewness = 0 means perfekt
skewness = 1 means degenerate

....
http://aerojet.engr.ucdavis.edu/gambithelp/html/users_guide/ug0304.htm#gc_exmesh
Thank you so much for replies
But I'm not convinced
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Old   February 12, 2013, 07:24
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Quote:
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But I'm not convinced
I will convince you:
generate an awfull mesh with skewness greather than 0.97
Then import in fluent, and do a check mesh
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Old   February 12, 2013, 07:30
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Quote:
Originally Posted by -mAx- View Post
I will convince you:
generate an awfull mesh with skewness greather than 0.97
Then import in fluent, and do a check mesh
I know in this case, the software displays an error message(failed mesh). But when mesh quality is low(not bad) solution takes a lot of time
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Old   February 12, 2013, 07:40
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no
the value of your skewness is low, which means your quality is good!
Again:
skewness ~0 means excellent!
skewness ~1 means very poor!

While you compare your both models,what is smallest cell size in both meshes.
And how many cells they have. (cf your post #7)
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Old   February 12, 2013, 08:00
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Quote:
Originally Posted by -mAx- View Post
no
the value of your skewness is low, which means your quality is good!
Again:
skewness ~0 means excellent!
skewness ~1 means very poor!

While you compare your both models,what is smallest cell size in both meshes.
And how many cells they have. (cf your post #7)
My PC is hanging and I dont know why GAMBIT does not run. I will contact you later.

THANKS IN ADVANCE
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