A Finite --Volume, Two-Layer Shallow Water Equation Model to Simulate Gravity Currents with Ambient Crossflows

The shallow water equations (SWE) are a popular choice in gravity current (GC) models because of the good balance between accuracy and computational effort. This work presents a two-layer SWE model developed for high Reynolds number GC that accounts for ambient crossflows often encountered in the environment. The mathematical model is written in conservative and divergent format to account for the possibility of naturally occurring discontinuities and is solved with the nonlinear HLL scheme using a finite-volume framework. The depth profile and front trajectory for a constant-volume release compare well to a similar model proposed by Hallworth et al. (1998). The proposed model is also tested with density intrusion experiments, and the front velocity results compare well for both coflow and counterflow currents.