My model is to build a ultrafine particle injection to laminar flow with the electric field fore. (2D, Steady,DPM). When I want to add the constant electric field as body fore using UDF, I met a compile error and following is my code:

#include "udf.h"

#define ELECTRIC_FORCE=1.0045

DEFINE_DPM_BODY_FORCE(particle_body_electric, p, i) {

real bforce;

if(i==0)

{

bforce=0;

}

else

{

bforce=-ELECTRIC_FORCE; /* electric force Y */

}

return bforce; } I noticed that I didn't use p as a parameter in the micro definition. But I don't know what's wrong with these seemingly simple lines.

I need your help!

Sincerely

I think the error is due to the define declaration It should be:

#define ELECTRIC_FORCE 1.005

Thank u for your advice. I've already corrected it. But I still have some problems with UDF-sometimes it can compile the file I difined, sometimes it didn't. It's the exact same file. I really don't know what's wrong with the fluent compiler. Usually it needs several times to get it complied and connected to the iretation.

Good luck to U!

I don't know the detail of your udf, but if you want to use some advanced features of UDF, you'd better to use compiled rather than interpreted.