This is a really basic question. I want to model the flow of gas through a pipe with only a thin layer of liquid on the outside of the pipe, each phase having different velocities. Also I would like to model very small particles through this pipe. Should I use the Eulerian Model for each of these simulations? Should I begin with the ASM model to calculate an initial solution and then use the Eulerian model for a more accurate result? Any hints or pointers on the best method of modelling this flow regime will be greatly apppreciated.

What about discrete phase model?

Yes I will use the discrete phase model for the small particles. I was just unsure whether the Algebraic Slip Mixture Model and Eulerian Model were able to model annular flow (not involving bubbly flow which Fluent implies in the user guide for the mixture model). My initial question was a little obscure.