Problem UDF for Turbulen viscosity
 

Hi all,

How i can retrieve variables of different domains inside the same macro? I have retrieve the liquid density value, gas density value and turbulent viscosity inside the same macro. I want set up the Turbulent viscosity in the secondary phase using "dispersed" as Turbulent Multiphase Model in the k-e model.

I tried with the following udf:

DEFINE_TURBULENT_VISCOSITY(mu_t_ke_air, c, phase_t)
{
Thread *mt; /* mixture or super thread*/
Thread **all_phase_threads; /* An array of all the phase threads */

mt = THREAD_SUPER_THREAD(phase_t);
all_phase_threads = THREAD_SUB_THRADS(mt);


/* all_phase_threads[0] is primary thread, */
/* all_phase_threads[1] first secondary phase thread */

real mu_tg;
real rho_l = C_R(c,all_phase_threads[0]);
real rho_g = C_R(c,all_phase_threads[1]);
real mu_tl = C_MU_T(c,all_phase_threads[0]);
mu_tg = mu_tl*rho_g/rho_l;

return mu_tg;

}

But, this udf gave the following erro:

THREAD_SUB_THRADS is an undeclared variable.

Anyone know why gave this erro. If anyone knows another way to do it, using other pointer, etc..., please tell me.

Thanks!!!!

Hello, Does anyone know the correct udf for modifying turbulent viscosity in k-epsilon per phase model? (for Euler-Euler)

I am using the following udf (modified as per my knowledge, from the basic udf for k-epsilon mixture model) But it does not seem to be taking the correct value of k, epsilon etc from the fluent:

"
#include "udf.h"


DEFINE_TURBULENT_VISCOSITY(mu_t_ke_air,c,t)
{

real rho_g, KE_g, D_g, mu_t_g;

rho_g = C_R(c, t); /* gas phase density */
KE_g = C_K(c, t); /* gas phase Kinetic energy */
D_g = C_D(c, t); /* gas phase epsilon */

mu_t_g= 0.09*rho_g*KE_g*KE_g/D_g;

C_UDMI(c,t,2) = mu_t_g; // (Calculated above)

return mu_t_g;

}
"

Hi Ekta,

I face similar problem for implementing turbulent viscosity. Even though I am implementing the exact same definition as given in the equations for Re_y, Re_t, f_mu to implement User Defined viscosity for Lam-Bermhorst and Yang-Shih model but the results are quite different.
Any ideas?

Thanks