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November 7, 2006, 09:32 |
Error due to y+ value
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#1 |
Guest
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Hi:
I am simulating flow of air in pipe (long pipe with lots of elbow, bends etc) by FLUENT. I am using standard k-e turbulent model with standard wall function. My questions are: 1. Should I check wall y+ or y* value? 2. Lets say the y+ value is in the limit 15-200. But according to the theory we know lower limit is 30. With this current simulation (i mean value 15) what kind of error (%) will be introduced to the pressure drop data? Will it be considerable or negligible? 3. Its a huge model (around 3 million cell) and I am afraid I cant refine the mesh anymore. What do you recommend from your experience? Thank you guys. Munni |
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November 8, 2006, 05:19 |
Re: Error due to y+ value
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#2 |
Guest
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Hi!
1. YES! y+ is extreamly importand, if you want to report drag - wall sher stress is calculated using the wall low - and that dependes on the wall function! 2. I am not so sure about that... 3. Use boundary layer option. that will give you a small wall disdance, but enables one to have the next cell larger. That reduces the number of cells. Ralf |
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