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-   -   References for Mixing-length calculation? (http://www.cfd-online.com/Forums/main/3297-references-mixing-length-calculation.html)

Ray March 28, 2001 05:28

References for Mixing-length calculation?
 
Hi,

Could anybody tell me some reference books or papers on how to calculate mixing-length in 3-D simulating? say, I have got the velocity field,etc...

Many thanks!

Ray

Selina Tracy March 28, 2001 17:44

Re: References for Mixing-length calculation?
 
Try

http://www.aero.obs-mip.fr/mesonh/book1/node1.html, http://www.cham.co.uk/phoenics/d_pol.../lec7-22.htm#6, http://opus.utah.edu/~smith/Research...siam/siam.html

Selina

Ray March 29, 2001 05:26

Re: References for Mixing-length calculation?
 
Thanks! Selina.

The problem rises from that in most turbulence modelling, the mixing-length is prescribed for model closure. Hence the mixing-length may be grid dependent. But physically, it should depend on the system operating conditions. So what I am concerning is if I can derive out the mixing-length from the computed flow field. Some work seems has been done for 2-D case, such as Von Karman's formula which related the mixing-length to the velocity profile. But how about 3-D? Any more clue or suggestion?

Ray

Christophe March 31, 2001 18:45

Re: References for Mixing-length calculation?
 
Well, it did not caught much of the context, but... mixing length should be close to the length scale given by kolmogorov's equation -for high Reynolds-:

mix_len =~ Cmu^(3/4) * k^(3/2) / epsilon

Also, if your flow looks like a single-bounded one (and wall is mostly homogeneous) you may apply von Karman's formula but both should remain the same close to the wall...

Yours,

Christophe


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