Hi there,

I need to provide different diffusivities for different user defined scalars, but FLUENT only offers 1 udf to be used to specify a diffusion coefficient. Has anybody a suggestion how to create scalar-dependent diffusivities? Thanks for your help.

Elmar

The index, last parameter, (see udf manual) specifies which uds the diffusivity is for. Thus write something like

if (k == 0)

return diff_for_uds_0 if (k == 1)

return diff_for_uds_1 etc...

So you can have different isotropic diffusivities for each scalar. Anisotropy . . . that's another matter.

Greg