[Linas]

I am working with a two-phase case, wherein each phase has only one species. Using DEFINE_SOURCE, I can remove mass from one phase. How do I add mass to the other phase?

Here is a simplified UDF to remove mass from one phase:

#include "udf.h"
#include "math.h"

/* Define the source term function */
DEFINE_SOURCE(species_add_lit3, c, t, dS, eqn)
{
real source;

source = 1;
dS[eqn] = 0;

return source;
}

In my actual UDF, the source is not constant but a function.

[cbooks77]

Mass must be conserved. Whatever you take from one phase (negative source) becomes positive source to other phase...