[diamondx]

Hello everyone,
I started learning UDF today, i created my first code. It's an easy source term that i apply on a SPECIFIC domain of fluid. the source is a x-momentum, here is my code:

#include "udf.h"

DEFINE_SOURCE(test,c,t,dS,eqn)
{
real xc[ND_ND];
real source;

C_CENTROID(xc,c,t);

if ((xc[0] == -0.135608)&&(xc[1] == 0.179728))
{source = 1000;
dS[eqn] = 0;}
else {source = 0;dS[eqn] = 0;}
C_UDMI(c,t,0)=source;
return source;
}

The UDF is interpreted/compiled without any error. this udf applies a source in the location(x,y). I should see a change in the velocity vector, right ? nothing happens, why ? I'm trying to simulate plsma actuators and in all the article that i read, this same udf code is used...