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-   -   Smagorinsky Dynamic Cosant in UDF (http://www.cfd-online.com/Forums/fluent/49641-smagorinsky-dynamic-cosant-udf.html)

Paolo Lampitella October 28, 2008 08:53

Smagorinsky Dynamic Cosant in UDF
 
Hi, i'm performing some tests on the LES module of Fluent with the turbulent channel flow.

I wrote an UDF to export my data in an external file but i can't find the Dynamic Constant in the variables. That is:

C_U(c,t) is the x_velocity

C_V(c,t) is the y_velocity

C_W(c,t) is the w_velocity

what is the command for the Dynamic Constant?

If there is not such a command, do you know if the following one:

C_MU_T(c,t)

which is the turbulent viscosity, is also valid with the LES model?

Thanks

sla June 17, 2009 03:40

Hello,

If it is needed for postprocessing you can extract a dynamic constant Cd by

Cd = mu_t/(rho*SQR(delta)*S);

where

mu_t=C_MU_T(c,t);
rho=C_R(c,t);
delta=pow(C_VOLUME(c,t),0.333);
S=Strainrate_Mag(c,t);


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