GRAVITY-DRIVEN FLOWS IN A TURBULENT FLUID.

The information and destruction of a gravity current in a turbulent fluid is examined in laboratory experiments. The current has a sharp density front at its leading edge, and a stable density stratification is established behind the front. The turbulence, characterized by a longitudinal turbulent diffusion coefficient K, tends to mix this stable stratification. Once the fluid is vertically mixed the gravity current front is destroyed, and the density varies smoothly with horizontal distance over a zone whose length increases with time due to the continuing longitudinal turbulent diffusion and buoyancy driving. It is found that the gravity current propagates over a distance L//1 before it is destroyed. At this point turbulent dissipation balances the buoyancy driving and frontogenesis is inhibited.