I'm having trouble with a UDF. My C_UDSI_G(c,t,UU), C_UDSI_G(c,t,UV), and C_UDSI_G(c,t,VV) commands are returning NAN values, and the code is crashing.

Does anyone know why? The code starts with:

#include "udf.h"

enum { UU, VV, UV };

DEFINE_SOURCE(u_source, c, t, dS, eqn) { dS[eqn]=0.; source= - C_R(c,t) * ( C_UDSI_G(c,t,UU)[0] + C_UDSI_G(c,t,UV)[1]; return source; }

There's lots more after that, but that's as far as the code gets before it returns errors.

Thanks in advance for help!

Hi

At the first iteration C_UDSI_G(c,t,XX) is not available yet.

So run fluent 1 or 2 iterations then hook your UDF to fluent.