Adding Source Terms in Specific Cells
 

I am modelling a 2 phase flow using VOF in FLUENT. I want to add some source terms in the N-S equations and energy equations. I need to add this source terms in the cells at the interface of 2 phases. I have written a UDF to identify these cells at every iteration.
I am using F_C0 and F_C1 to get the index of cells at the interface. For example, real cell_t c1 = F_C0(c,t). Then I storing this c1 in a user define memory location(C_UDMI).
Now, I want to apply source in these cells with the index c1. So my question is can I use a if condition in DEFINE_SOURCE like:

if(c == C_UDMI(c,t,i))
{
source = .................
}
else
{
source = 0;
}

Is it the correct way or am I doing it wrong? Any help is much appreciated.
Thanks in advance.

I suggest you to use other approach
once you've found c0,t0,c1,t1
use so you will get a flag to check if cell is adjusted to interface

in define_source you'll need to check that flag

Thanks a lot for your suggestion. I will try that. Till now I was going with
if(c == C_UDMI(c,t,i))
{
source = ...............
}

Also can you suggest if I am doing it right by using F_C0 and F_C1 to get the interfacial cells? I have been stuck with this for a long time now without any help. I am new to UDF writing and have written a UDF to track the interfacial cells but it is not working. I had posted this earlier in the forum also.

Thanks.

from my point of view, if you need boundary between two phases while you are using VOF, then you don't need c0,c1

thre is a macro to check phase vof concentration C_VOF which will return you [0..1] depends on the phase inside the cell

so your you may check C_VOF in cell and consider it's boundary (which you called interface) in case C_VOF >0.5 and C_VOF <= 1
value 0.5 could be different

hope you get the idea

Actually earlier I was using this criteria only(0.01<C_VOF<1). Then I read a few papers and in those, authors had continuously tracked the interface using UDF. This is because, I am melting solid so when solid melts, iso surface for volume frction will change and I need to track the interface. So, I started writing a UDF for this taking help from the forum.

Thanks