Intrusive gravity currents propagating into two-layer stratified ambients: Vorticity modeling

A simplified model is developed for intrusive gravity currents propagating along the interface of a two-layer stratified ambient. The model is based on the conservation of mass and vorticity and it does not require any empirical closure assumptions. A parametric study conductedwith this model reproduces the correct behavior in various limits and is consistent with previously reported experimental observations. Specifically, it predicts the formation of equilibrium intrusions when the intrusion density equals the depth-weighted mean density of the two ambient layers. It furthermore demonstrates the existence of nonsmooth limits under certain conditions. An energy analysis shows that under nonequilibrium conditions the intrusion gains energy. The predictions by the parametric study are furthermore compared to two-dimensional direct numerical simulation results and very good agreement is observed with regard to all flow properties.