[Sorabh]

I was trying to include the following source term in udf:



This is the code snippet:

DEFINE_SOURCE(perfusion,c,t,dS,eqn)
{
	real physical_dt,temp_old,temp_now,T_derivative,source;
	physical_dt = RP_Get_Real("physical-time-step");
	if (physical_dt > 0.1)
	{
		temp_old= C_T_M1(c,t);
		temp_now=C_T(c,t);
		T_derivative=(temp_now-temp_old)/physical_dt;
	}
	source = -tq*rho_b*wb*cb*T_derivative;
	dS[eqn]=0;

	return source;
}

However I am not getting any change in my results. What am I doing wrong?
Thanks..

[AlexanderZ]

most likely problem comes from line
temp_old= C_T_M1(c,t);

from manual

Note that data from C_T_M1 is available only if user-defined scalars are defined. It can also
be used with adaptive time stepping.

check waht you get here temp_old= C_T_M1(c,t);

best regards