[mohibanwar]

Good Morning Everybody,

Thank you so much for reading my time consuming post about a very fundamental problem.

I am currently writing a UDF to calculate the (Normal) specie mass fraction gradient at curved wall. I want to store the gradient in UDM for future use at present.

I have tried to give a try and write the basic UDF from the previous examples and UDF manual. However, there are some problems that i cannot identify to interpret or compile it. Further i am not sure the present concept will work or not.Your Correction is highly appreciated in this regard.

Thank you from the core of my heart.
My UDF is as following:


#include "udf.h"

DEFINE_ON_DEMAND(gradient)
{
Domain *d;
Thread *t,tc;
face_t f;
cell_t c;
d=Get_Domain(1);
tc=Lookup_Thread(d,8); //Wall ID
real A[ND_ND],ds,es[ND_ND],A_by_es,dr0[ND_ND];
begin_f_loop(f,tc)
{
real rho;
rho = 1.17;
tc = THREAD_T0(t);
c = F_C0(f,t);
BOUNDARY_FACE_GEOMETRY(f,t,A,ds,es,A_by_es,dr0);
C_UDMI(c,tc,0)=((F_YI(f,t,0)*rho)-(C_YI(c,tc,0)*rho))/ds;
}
end_f_loop(f,t)
}