[bgu]

Hi experts
I guess I was not clear enough stating my problem previously, I'll try to do better now.
In a 3D (x,y,z) domain I need to solve a scalar equation using UDS. The scalar, f, varies only in the (z) direction, namely, df/dz=C(z)*f, C(z) is a function which I compute in the UDF.
I thought of solving this using the Fluent UDS solver with convective flux=0, diffusion coefficient=1 and a suitable source term S.

the UDS equation will look like this: -d/dxi(df/dxi)=S

Here is the problem: the source term is valid only for (z), thus, both d/dx and d/dy=0. How to pass this information to the UDS solver?

Thank you