Temporal Observations of Interfacial Layer between Fluids of Different Density

Abstract

The entrapped wedge is a specific type of stratified flow problem that is found in estuaries when a barrage is used to control water levels. To avoid problems with water quality, it is essential that any wedge be removed. The sensible mechanism by which this should occur is via the momentum of the freshwater flow. To investigate this, a laboratory investigation of the erosion of an entrapped saline wedge caused by a buoyant overflow has been undertaken. The shear flow has been found to induce mixing at the interface between the two fluids, and a mixed layer results. The characteristics of the layer have been found to change with time with two different mechanisms being identified. The behavior of the layer depends on the test conditions, in that certain combinations of velocity, depth, and density difference yield different mechanisms of erosion. The temporal behavior of the interfacial layer with various freshwater velocities and depths and density differences are presented.