Fluctuations in the interface between air flows of different speeds
 

So the problem I'm working on is as follows. I have a cylinder of radius r1. Air flows in through a hole of radius r0<r1. This air is going to have mean velocity U0. I'm interested in the material surface between the jet and the surrounding pipe. More specifically fluctuations in that surface. I'm trying to think of a good way to model it using an FEM simulation. Does anyone have any suggestions or know of any previous work?