The motion of gravity currents that simultaneously flow on and drain from a step

Releases of dense fluid propagate as gravity currents over horizontal surfaces driven by buoyancy associated with their excess density relative to the surroundings. They may surmount distant barriers. This study investigates the potential confinement of gravity currents theoretically in the situation where the initial motion occurs within a topographic depression, from which the fluid climbs a step and flows away over a horizontal surface while simultaneously draining back into the depression (see fig. 1). At very large-scales, this configuration is of relevance to volcanic surges that are initially confined within a crater, while at more
moderate scales, it is of relevance to the topographic confinement of dense pollutants within water courses.