Simulations of axial mixing of liquids in a long horizontal pipe
 

Good morning! We are working on a project of CFD "Simulations of axial mixing of liquids in a long horizontal pipe"

Which model can we use for simulating this kind of phenomenon (two types of fluid of different viscosity and density enter the pipeline one after another and produce the mixed zone that we need to study): Is it "multiphase, mixture or eulerian"? And could anyone provide some more details about setting the boundary conditions after defining the model?

Thank you for your help!