[ICEM] Negative grid occured at boundary layer

Sergeyevichsky · April 5, 2017, 13:29

Hi guys
In order to realize y+<1, 2e-6mm first boundary layer height has been set in ICEM using structure grid. But once spacing is less than 3e-4mm I set, negative grid will be occurred. And most strangely, the negative grid occurred at inlet and outlet all the time. No matter how I adjust spacing but increasing spacing more than 3e-4mm. It has perplexed me the whole day.
Sincerely
Lintao

kad · April 5, 2017, 21:51

Your mesh size might interfere with your geometric tolerance. Try lowering the value for tri tolerance under model/units.

Far · April 9, 2017, 08:52

Quote:

Originally Posted by Sergeyevichsky

Hi guys
In order to realize y+<1, 2e-6mm first boundary layer height has been set in ICEM using structure grid. But once spacing is less than 3e-4mm I set, negative grid will be occurred. And most strangely, the negative grid occurred at inlet and outlet all the time. No matter how I adjust spacing but increasing spacing more than 3e-4mm. It has perplexed me the whole day.
Sincerely
Lintao

divide the edge on circular boundary into more parts by splitting it.

Sergeyevichsky · April 23, 2017, 06:20

Quote:

Originally Posted by kad

Your mesh size might interfere with your geometric tolerance. Try lowering the value for tri tolerance under model/units.

I sorry for later response and thanks for you help.
The method is very well.
Thanks
Lintao

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April 5, 2017, 21:51		#2
kad Senior Member Join Date: Feb 2013 Location: Germany Posts: 200 Rep Power: 24	Your mesh size might interfere with your geometric tolerance. Try lowering the value for tri tolerance under model/units.