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derivation of epsilon equation of k-epsilon model

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Old   April 2, 2007, 19:32
Default derivation of epsilon equation of k-epsilon model
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Ricardo Rezende
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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!

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Old   April 3, 2007, 15:30
Default Re: derivation of epsilon equation of k-epsilon mo
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Richard
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Ricardo, You can find the complete epsilon equation in this paper

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

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

good luck! Richard
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Old   April 3, 2007, 16:07
Default Re: derivation of epsilon equation of k-epsilon mo
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pennysworth
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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.
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Old   April 5, 2007, 04:33
Default Re: derivation of epsilon equation of k-epsilon mo
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p
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i'll get it (hand written material)scanned and send you.
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Old   April 10, 2007, 13:11
Default Re: derivation of epsilon equation of k-epsilon mo
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Ricardo Rezende
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Thaks for all for your help.
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Old   May 1, 2007, 05:38
Default Re: derivation of epsilon equation of k-epsilon mo
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Jane Hockey
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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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