Correlation of Mixed Layer Growth in a Double-Diffusive, Salt-Stratified System Heated From Below

Abstract

Although many mixed layer growth correlations have been developed for stratified solutions which are eroded by mechanically driven mixed layers, little has been done to determine their applicability to solutions for which erosion is thermally driven. In this study entrainment rates have been determined from measurements of mixed layer growth in salt-stratified solutions heated from below. Entrainment data have been obtained for Richardson numbers in the range 80 < Ri < 1000, and when normalized with respect to the mixed layer convective velocity, the data are well correlated in terms of Ri−1. The correlation also agrees with published data obtained at larger and smaller Richardson numbers for both thermally and salt-stratified solutions heated from below. Predictions based on use of the correlation in a mathematical model of mixed layer development are in excellent agreement with measured mixed layer heights and temperatures.