Tips for air entrainment/bubbles? + steady state multiphase models
 

Can anyone give me some tips on simulating bubbles in a model? Specifically the bubbles are generated by air entrainment.

The model I am looking at is a spillway where the water flow should generate bubbles at the bottom of the tunnel.

I was previously using a VOF model with two Eulerian phases, H20 and Air and in 2D simulations I have a mesh of around 1mm and a timestep of 0.1ms. However the result seems a little off when looking at the volume fraction scalar results.

Also, is it possible to run a VOF model in steady state? I attempted to do this, but the results were extremely erratic. Are there any ways to get an accurate multiphase model using a steady state? There is no temperature change in my model if that helps.

A picture of my model (running at the moment) has been attached to show the sort of simulation I am looking at:
http://i.imgur.com/XKAD6bE.png?1

I am relatively new to multiphase models, all my knowledge of which has been self taught, so any advice would be appreciated on the finer options of the models.

Thanks