Behavior of Density Currents on an Incline

Abstract

Investigation of the behavior of salt solution released down a sloping surface in a tank of freshwater is reported here. Analysis indicates that the dense layer spreads in all directions at a rate proportional to the entrainment coefficient. Observations and measurements revealed a variety of phenomena depending strongly on the buoyancy flux, Richardson number, and the angle of incline. At small slope (∼<1/10) flow was found to be subcritical with negligible entrainment. As the slope increases, flow becomes supercritical and periodic interfacial instabilities appear. Growth and subsequent breakup of these instabilities were found to be the main mechanism for entrainment. Mean layer velocity away from the source can be estimated from the initial conditions and the angle of incline.