Ramesh Chandra Mishra


i am solving an equation which requires concentration gradient as a term. So i write concentration as mass fraction*density to a C_UDSI and then use C_UDSI_G to solve the equation. But I am getting zero everytime. Please note that i don't disable solving the equation for UDS. Is it because of that or there is something to be done in my case file?

A snippet of code is as follows:

thread_loop_f(t, d)
        F_CENTROID(x, f, t);
if (x[0] >= 108  && x[0] <=  126 &&  x[1] == 18 && x[2] >= 90  && x[2] <= 126 )
co = F_C0(f, t);              
to = THREAD_T0(t);      //obtaining corresponding thread of adjacent cell
real integrand;
real conc_grad_roof;
real mu_t_roof = C_MU_T(co,to);        //turbulent viscosity 
C_UDSI(co,to,0)= C_YI(co,to,0) * RHO_1;   //storing concentration of CO as user defined scalar(UDS)
conc_grad_roof=(C_UDSI_G(co,to,0)[1]);       //concentration gradient of CO
integrand = (mu_t_roof /0.7)*conc_grad_roof;     //TURBULENT POLLUTANT FLUX
PCH_turb_roof -= integrand*NV_MAG(A);            //Overall value of PCH integral