[Nek5000-users] variable density incompressible flow

[nek5000-users at lists.mcs.anl.gov]

Hi

I am a total newbie with regards to nek5000. I want to simulate a variable density incompressible flow where the variation in density is brought about by the motion of an interface separating two fluids. The interface is tracked via a level set method. To achieve this, an appropriate source term is added in the continuity equation, thus making the velocity field divergent.  To do this using nek5000, I need to know how to input a user defined divergence of velocity. Could anyone throw some light on this or guide me to some documentation/example which would help me? 

Thanks,
Regards.

-Navin Fogla