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k-? two equation turbulence model

k-? two equation turbulence model

k-? two equation turbulence model

(OP)
I need to find two parameters in order to implement it in the CFD software we are currently using. The two parameters are; Eddy k Energy Field and Eddy length field.

I have been told that the length can be averaged between min and max values of the Nikuradse formula, and the energy by μ / (ρ * L), where L is initial length. I have not been able to find the Nikuradse formula, what is it?

Is it some other way of finding these two parameters?

RE: k-? two equation turbulence model

(OP)
I see... The Haaland, Darcy-Weisbach, Colebrook etc. I have in my possetion. I need to find an equation that can estimate length of eddys and energy in eddys. This is to find friction factor f...?!

RE: k-? two equation turbulence model

eddy diffusivity and the
velocity profile is discussed here,

http://www.journalarchive.jst.go.jp/jnlpdf.php?cdjournal=jnst1964&cdvol=5&noissue=7&startpage=354&lang=en&from=jnlabstract

 

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: k-? two equation turbulence model

(OP)
I have looked in the previous link you referred to, and the turbulence model descussed in the paper are the mixing length turbulence model (...which are still widely used), not the k-ε two equation turbulence model. I am not a CFD expert, and so I have not figured out where to start searching. The eddy energy can be found from the eddy length and fluid property data, but I need to find an approximation of the initial eddy length based on input data.

RE: k-? two equation turbulence model

Try a Google of "k-ε two equation turbulence model"  
Pick the first free one,
http://www.texstan.com/m3.php

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: k-? two equation turbulence model

Also google k-w (Greek letters kappa and omega) turbulence model.

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