Hi! I want to define a neuman boundary condition (dYi/dn = cte) for a mass fraction Yi in the interior surface. Please tell me how to do it! Thanks

Hi, I have written an UDF for neuman boundary condition for species mass fraction at the pressure outlet. It is compiling and after loading when i want to hook it the udf file "species_grad" is displaying at BOUNDARY CONDITION-FLUID-SOURCE TERM" instead of at species mass fraction at the pressure outlet. Pls look it. it may help u.

#include "udf.h"

DEFINE_SOURCE(species_grad,cell,thread,dS,eqn)

{

float source=0.0;

begin_c_loop(cell, thread)

{

C_YI_G(cell,thread,1)[0]=0.;

source=C_YI_G(cell,thread,1)[0];

/*dS[eqn]=0.;*/

}

end_c_loop(cell,thread)

return source;

}

If u can solve my problem i will be great full to u.

sisir