Standard-k-€ vs. low-Re-k-€

tH3f0rC3 · June 10, 2011, 01:33

Hi,

I have a question about the difference in the calculation of the two different turbulence models Standard-k-€ (high-Re) and a low-Re model such as LaunderSharmak€.

I think I have read that the high-Re model is proned to calculate turbulent eddies bigger than they are in reality. Alleged due to great values of viscosity.
Because of that it is allegedly better to use a low-Re model such as LaunderSharmak€ to avoid this problem.

I'm not sure if this is right, so if anyone knows something more about that please let me know.

Best Regards,
tH3f0rC3

gregor · June 10, 2011, 03:46

hi,

low-Re models are used in wall bounded flows with resolved boundary layer since turbulent fluctuations and therefore the turbulent viscosity (leads to a low Reynolds number) are damped near walls. So when to use a low-Re model depends on your case. Different turbulence models normally have different scopes and it is your job to find the right one for your case

you can find some details in the Fröhlich BookLarge Eddy Simulation turbulenter Strömungen p. 52

gregor

June 10, 2011, 01:33	Standard-k-€ vs. low-Re-k-€	#1
tH3f0rC3 Senior Member Join Date: Mar 2011 Posts: 155 Rep Power: 4	Hi, I have a question about the difference in the calculation of the two different turbulence models Standard-k-€ (high-Re) and a low-Re model such as LaunderSharmak€. I think I have read that the high-Re model is proned to calculate turbulent eddies bigger than they are in reality. Alleged due to great values of viscosity. Because of that it is allegedly better to use a low-Re model such as LaunderSharmak€ to avoid this problem. I'm not sure if this is right, so if anyone knows something more about that please let me know. Best Regards, tH3f0rC3

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June 10, 2011, 03:46		#2
gregor Member Gregor Olenik Join Date: Jun 2009 Posts: 66 Rep Power: 5	hi, low-Re models are used in wall bounded flows with resolved boundary layer since turbulent fluctuations and therefore the turbulent viscosity (leads to a low Reynolds number) are damped near walls. So when to use a low-Re model depends on your case. Different turbulence models normally have different scopes and it is your job to find the right one for your case you can find some details in the Fröhlich BookLarge Eddy Simulation turbulenter Strömungen p. 52 gregor