CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM (http://www.cfd-online.com/Forums/openfoam/)
-   -   About the nut wall function in RAS (http://www.cfd-online.com/Forums/openfoam/70120-about-nut-wall-function-ras.html)

spwater November 15, 2009 06:11

About the nut wall function in RAS
 
Hello everyone,
This is Pei, I have a question about the wall function of nu in RAS model, I found in the code,

nutw[faceI] = nuw[faceI]*(yPlus*kappa_/log(E_*yPlus) - 1.0)

However, the book I am reading says it should be

nutw[faceI] = nuw[faceI]*(yPlus*kappa_/log(E_*yPlus) )

Can angone explain the difference? Thank you very much!

Anne Lincke October 28, 2011 10:37

Hey Pei,

In the log-Layer we can assume that nu_t >>nu
Therefore we can approximate

nuw[faceI]*(yPlus*kappa_/log(E_*yPlus) - 1.0) = nuw[faceI]*yPlus*kappa_/log(E_*yPlus)-nuw[faceI]
~~nuw[faceI]*yPlus*kappa_/log(E_*yPlus)


All times are GMT -4. The time now is 09:24.