[jacek]

I'm not sure about some nuance. According to the definition this makro is based on cell basis and the output for mass generation is: kg/m3/s.
So I put simple macro:


DEFINE_SOURCE(ZrMas, ce, th, dS, eqn)
{
real source;

source = 0.002;
dS[eqn] = 0;
return source;
}.
Now the output form this UDF is not 0.002 kg/s from a particular cell where at the moment loop is executed but Fluent treats it as 0.002 kg/m3/s. Then, Fluent recalculates this mass source by multiplying by volume:

0.002 [kg/m3/s] * v [m3].

Thus we get absolute mass generation in zone/thread in kg/s.

But I'm not sure if v is the cell volume or a mean volume of cell yielded by calculation:

Zone Volume / Number of Cells.

It would be important if cells in zone/thread were of different sizes.

I suppose that v is current cell volume since DEFINE_SOURCE runs on cell basis. But I'm not sure.