Mixed Layer Development in a Double-Diffusive, Thermohaline System

Abstract

A double-diffusive, thermohaline system has been studied under laboratory conditions involving uniform heating from below. Shadowgraph visualization has been used with temperature and salt concentration measurements to investigate mixing layer development and the onset of diffusion layer instabilities. Such instabilities were observed to occur in two of the experiments and were approximately predicted by an existing stability criterion. Interfacial boundary layers which separated the mixing layers from the diffusion region ranged in thickness from 10 to 30 mm and were characterized by a nearly uniform temperature and a nonlinear vertical salt concentration distribution. The rate of mixing layer development decreased with increasing salt concentration.