Modelling Purging of a Density Stratified Cavity

Natalie

Hello everybody, I am currently modelling river flows whereby the river channel has a cavity within the floor which is filled with water of a higher density (saline water). I need to be able to model the purging (or emptying) of the cavity by an overflow of fresh water, while still including the free surface effects. The water and the saline are miscible, so the volume of fluid model doesn't work for the fresh water/salt water mixing. I am using the k-epsilon turbulence model (even though I anticipate the purging rate of the saline pool will be too high with this method). I am at a loss as to which model (multiphase or species mixing) I should be using. I hope someone has had some experience modelling these kinds of flows and will really appreciate any insight anyone may have. Thank you, Natalie