Hi, guys. I need to write an UDF for volumetric heat production in a 3D problem. The heat source strength is a say parabollic function of say Z coordinate, e.g. q_dot=2*z*z-5z+3 W/m^3. Please help me. Thank you.

#include "udf.h"

DEFINE_SOURCE(heat_source,c,t,dS,eqn) { real x[ND_ND]; real source;

C_CENTROID(x,c,t);

source = 2*x[2]*x[2]-5*x[2]+3; dS[eqn] = 0.0;

return source; }

/*Z coordinate, e.g. q_dot=2*z*z-5z+3 W/m^3. Hook this UDF to appropriate panel for energy source. PS: I havent tested it for any error.*/

------- Sujith S Nair

Thanks a lot.

[leila2]

hi,
I need to write an UDF for 2D heat source (on a face).The source has a parabolic function (source=x*x+2*x+1 ) Do I use C-CENTROID or C-FACE in my programm?
Please help me. Thank you.
DEFINE_SOURCE(energy_source,c,t,dS,eqn)
{
real x[ND_ND];
real source;
cell_t c;
begin_c_loop(c,t)
{
C_CENTROID(x,c,t);
source = x*x+2*x+1;
dS[eqn] = 2*x+2;
return source;
}
end_c_loop(c,t)
}

[m zahid]

hi
i am facing the similar problem. my UDF of source term is showing zero output. here is my Udf , if anybody know the problem please help me .

DEFINE_SOURCE(xmom,c,t,dS,eqn)
{
real x[ND_ND];
real source,ve;
C_CENTROID(x,c,t);
ve=sqrt((pow(C_U(c,t),2.0)+pow(C_V(c,t),2.0)+pow(C _W(c,t),2.0)));
source =-1.225*0.2*0.55* C_U(c,t)*ve;
C_UDMI(c,t,0)=source;
return source;
}


thanks