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fLUENT UDF user-defined tke at the wall

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Old   August 4, 2011, 20:36
Default fLUENT UDF user-defined tke at the wall
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ralph
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Hi,
I am trying to force the kp( turbulence kinetic energy at the centre of cell immediately adjacent to the wall) to certain value but I am not sure if my method is correct. This is what i wrote in the user-defined function. Is this correct?

C_K(c0,t0)= 0.1689;

Thanks
Ralph
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Old   August 5, 2011, 01:25
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Ji Junjie
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Quote:
Originally Posted by syler3321 View Post
Hi,
I am trying to force the kp( turbulence kinetic energy at the centre of cell immediately adjacent to the wall) to certain value but I am not sure if my method is correct. This is what i wrote in the user-defined function. Is this correct?

C_K(c0,t0)= 0.1689;

Thanks
Ralph
I think C_K is read only. The usage of C_K is just to compute turbulent viscosity. So I think you can directly change the expression of turbulent viscosity using the following macro.

#include "udf.h"
DEFINE_TURBULENT_VISCOSITY(user_mu_t,c,t)
{
real mu_t,rho,k,d;
rho = C_R(c,t);
d = C_D(c,t);
if(adjacent to the wall.......) // judge whether a cell is adjacent to the wall
k=0.1; //assume you constant is 0.1
else
k = C_K(c,t);

mu_t = M_keCmu*rho*SQR(k)/d;
return mu_t;
}
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