CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Main CFD Forum (http://www.cfd-online.com/Forums/main/)
-   -   WALL FUNCTION: Implement process (http://www.cfd-online.com/Forums/main/7568-wall-function-implement-process.html)

boling2002 May 21, 2004 01:58

WALL FUNCTION: Implement process
 
I am currently working on implementing the wall function to Wilcox wall function.Now I am trying the case for flat plate. My code is using JST scheme. The main steps I am using are: 1) Compute u_{\tau} by using y^{+}=1/k ln( u^{+} + B with given velocity from the first interior cell. 2) Compute \tau_{w} using u_{\tau} and \rho. 3) Using the integral x-component of \tau_{w} multiply the maginitude of surface vector. 4) Set the engergy item to zero since I am working for steady adibatic case.

Is there anything wrong in my implementation, I could not get the resonable results. Could anyone give me your hand ?

Thanks

boling2002 May 23, 2004 17:55

Please help me.
 
thanks .

Jonas Bredberg June 8, 2004 09:32

Re: WALL FUNCTION: Implement process
 
Hi there,

I guess you simply forgot to tell us that you have included the following functions for k and omega: k=u_tau/sqrt(C_mu) omega=u_tau/(sqrt(C_mu)*\kappa*y) Furthermore it seems to be a typo for the log-law: u+=log(y+)/\kappa+C, \kappa=0.41, C=5 When computing u_tau (from the log-law and u+=U/u_tau) you could maybe iterative some times, as the log-law needs y+ which involves u_tau itself as: y+=u_tau*y*\rho/\mu What you mean by multiplying tau_w with the surface vector, and don't know. Though I guess you do it rightly. Tau_w is the surface tension which is introduced in FVM as a source term by multiplying with the appropriate surface-area.


All times are GMT -4. The time now is 17:28.