[gopalpandey]

Hi Everyone,
I have written the following UDF to modify the turbulent viscosity for the standard k-epsilon model to consider the influence of the local temperature gradient.

can please someone help me with what's wrong with the code? I will upload the errors in the comments!

#include "udf.h"
#include "math.h"
DEFINE_TURBULENT_VISCOSITY(m_mu_t,c,t)
{
real mu_t;
real rho=C_R(c,t); /*accessing density of the cell */
real k=C_K(c,t); /*accessing kinetic energy of the cell */
real d=C_D(c,t) /*accessing rate of dissipation of kinetic energy */
real c1=1.2,c2=1,ct; /*defining some empirical constant*/
real t_temp=C_T(c,t) /*accessing the cell temperature*/
real mtao_z=0.1; /*defining empirical constant*/
real m=0.1;
real mtao,c_mu;
real f_mz,tg,a;
real div_t=C_T_G(c,t); /*use of macros to access the temperature gradient*/
a=331*SQRT(t_temp/273);
mtao=SQRT(2*k/a);
if(mtao>mtao_z) /*applying Heaviside function */
f_mz=SQR(mtao)-SQR(mtao_z);
else
f_mz=0;
tg=(div_t*power(k,1.5))/(t_temp*d);
f_mt=(SQR(mtao)-SQR(m))*f_mz;
ct=1+(1.2*power(tg,0.6))/(1+f_mt);
c_mu=0.09/ct;
mu_t=c_mu*rho*power(k,2)/d;
return mu_t;
}



thanks in advance!

[Siba11]

I think your syntax for power function is incorrect.

It's pow(a,b).