k-? two equation turbulence model 1

[blckwtr]

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 ? / (? * 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?

 

[BigInch]

Equation 3 here,

http://www.ipt.ntnu.no/~jsg/publikasjoner/paper01b/Amsterdam2001FrictionPaper.pdf

**********************
"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/

 

[blckwtr]

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...?!

 

[BigInch]

eddy diffusivity and the
velocity profile is discussed here,

http://www.journalarchive.jst.go.jp...ssue=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/

 

[blckwtr]

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-? 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.

 

[BigInch]

Try a Google of "k-? 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/

 

[btrueblood]

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