Mixing experiments on fluid released near the closed end of a two-dimensional channel

Abstract

In a series of laboratory experiments we found that if a line plume is located a finite distance from the closed end of a channel, the fluid between the plume and the end wall becomes partially mixed and a gravity current propagates towards the open end of the channel. In the experiments a steady state is rapidly attained in which the gravity current has approximately one half the depth of the channel and the filled region near the wall has the same density as the fluid in the gravity current. We describe a simple theory to model our experiments and predict the speed and concentration of the gravity current. The situation is very different from the case where the plume is located at the end wall. In the latter case no filled region develops and the gravity current remains significantly thinner and more concentrated. However, in both cases the gravity current travels with the same speed.