Entrainment across a density interface inside a flume compartment

Entrainment characteristics across a density stratified interface inside a two-dimensional flume compartment were investigated experimentally. The interface was formed by a generally quiescent body of fresh water floating on top of sea water. Relative motion between the two stratified layers was induced by a uni-directional flow below the compartment. This in turn set up flow circulations within the seawater layer. In the tests, the compartment length, the mean velocity of the sea water flow, and the height of the density interface above the compartment bottom were varied in order to evaluate their influence on the entrainment rates. The effects of slotted barriers across the compartment bottom on the entrainment rates were also examined. The entrainment coefficient can be expressed in terms of dimensionless parameters related to significant flow and geometrical parameters. By means of regression analyses of the test data, an empirical equation for the entrainment rate was established.