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-   -   derivation of epsilon equation of k-epsilon model (http://www.cfd-online.com/Forums/main/13243-derivation-epsilon-equation-k-epsilon-model.html)

 Ricardo Rezende April 2, 2007 19:32

derivation of epsilon equation of k-epsilon model

Does anybody have the deduction of the transport equation for the rate of dissipation of the k-epsilon model? I already deduced the equation for k but the equation for epsilon I am having difficulties. Can anybody help myself? Thanks!

 Richard April 3, 2007 15:30

Re: derivation of epsilon equation of k-epsilon mo

Ricardo, You can find the complete epsilon equation in this paper

Rodi, W. and Mansour, N.N., Low Reynolds number kâ€"eps modelling with the aid of direct simulation data. J. Fluid Mech. 250 (1993) 509â€"529.

http://journals.cambridge.org/action...=-1&aid=339411

good luck! Richard

 pennysworth April 3, 2007 16:07

Re: derivation of epsilon equation of k-epsilon mo

The epsilon equation that is used in the k-epsilon model is itself modelled after the k equation, because the exact equation is not useful from a modelling point of view. Thus, similar to the k equation, on has

D/Dt(eps) = Prod_eps + diffus_eps - destruct_ eps

Production is motivated by self-similar evolution of homogeneous shear turbulence. Destruction is motivated by self-similar decay of homogeneous turbulence, and diffusion is modelled in a gradient diffusion form just like diffusion of k.

 p April 5, 2007 04:33

Re: derivation of epsilon equation of k-epsilon mo

i'll get it (hand written material)scanned and send you.

 Ricardo Rezende April 10, 2007 13:11

Re: derivation of epsilon equation of k-epsilon mo

Thaks for all for your help.

 Jane Hockey May 1, 2007 05:38

Re: derivation of epsilon equation of k-epsilon mo

I'm having trouble with this derivation as well. Turbulence is giving me grief because stats really isn't my strong point. If it's not too much trouble, would it be possible for me to take a look at the derivation as well?

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