Abstract

In this seminar I will discuss some recent results from Direct Numerical Simulation of a gravity current. Of particularly interest is the relation between entrainment into the current and the turbulence in its interior. Making use of recent progress in the understanding of entrainment in turbulent plumes and jets (JFM 782 pp. 333-355), we decompose the entrainment into contributions due to turbulence production, buoyancy, and boundary effects. We show that boundary effects are small for the problem under consideration and restrict attention to an idealised case with free-slip boundary conditions. We explore the parameter space by varying the slope angle and study the stratified turbulence in the interior and parameterise the eddy viscosity and dissipation rate.