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Length scale in k-omega models?

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Old   May 30, 2014, 14:33
Default Length scale in k-omega models?
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Hi;

Does anyone know why the length scale for k-omega models differs by a constant?

-In Wilcox for k-omega: length scale = sqrt(k)/omega

-In Fluent and other codes : length scale = cmu^(-1./4)*sqrt(k)/omega

-In Menter 1994 for k-omega SST: length scale = sqrt(k)/(cmu*omega)


Does the definition change between k-omega and k-omega SST? Why?

Thanks and good day,

Mary
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Old   June 1, 2014, 12:41
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Because of the difference in the definition of the omega variable. The length scale is defined as

L = k^3/2 / epsilon

When people derive the omega equation from the epsilon equation, there has been differences in the definition of the omega variable. The difference is the inclusion/exclusion of the variable Cmu. However, they adjust the constants to account for this difference, You need to be careful in using the proper constant values associated with each variable depending on the definition.
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