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-   -   Kolmogorov scale .... LES (http://www.cfd-online.com/Forums/main/9660-kolmogorov-scale-les.html)

 LESer August 8, 2005 08:45

Kolmogorov scale .... LES

Hello,

I am doing some LES of a reacting flow and I need to calculate some values. How can I calculate the Kolmogorov timescale and the Kolmogorov Reynolds Number? Also how can I calculate the dissipation rate (epsilon)?

Thanking you all.

 yuan August 12, 2005 00:01

Re: Kolmogorov scale .... LES

I guess you need read a textbook. Select large scales, estimate the dissipation scales by using the Komogorov relations and then estimate epsilon.

 maphd July 2, 2015 19:48

Hello LESer,
Did you find how to calculate kolmogorov length scale in LES? I really appreciate if you could give me some help on this.
Thanks,

 FMDenaro July 3, 2015 03:38

there is no Kolmogorov scale in LES ! the smallest scale is defined by the filter lenght, not by the molecular viscosity and lies in the inertial subrange.

 maphd July 3, 2015 05:36

FMDenaro thank you very much for your reply. Can you tell me a way to calculate this smallest length scale? I just need a way to calculate something similar to kolmogorov length scale? Can I write a user defined function for kolmogorov length scale maybe? If you could give me some help on this I really appreciate it.
Thank you very much

 FMDenaro July 3, 2015 05:54

Kolmogorov scale is dictated by the physics of the problem.
LES provides the smallest scale at about twice grid step size. That has nothing to do with kolmogorov scale

 maphd July 3, 2015 06:01

FMDenaro, thank you very much for your reply. Is there any way I can calculate and see that smallest scale in Fluent? I really appreciate your help. I just need to calculate something corresponding to kolmogorov length scale in LES. Thanks a lot.

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