[cpadam]

I want to model the flow of a slug of water driven through a pipe by a high-pressure gas (hundreds of atmospheres). The gas and slug are initially at rest and discretely separated in a pipe with one end sealed and one end open to the atmosphere. The gas is at some initial pressure. At t=0 the gas is allowed to push (and mix with) the water slug. After traveling a short distance, both phases discharge into the atmosphere from the open end of the pipe.

The two things I want to get out of this simulation are the dispersion pattern of the liquid slug as it breaks up in and out of the pipe, and also the pressure drop in the gas at various locations.

How should I approach this problem in Fluent? That is, what multiphase model would be appropriate, and should I model the liquid with a dynamic mesh? I have only done single-phase transient models in Fluent so far.

Thanks.