Fluxes of heat and salt across a diffusive interface in the presence of grid generated turbulence

Abstract

The transport of heat and salt across an interface, which has been stabilized by a salinity contrast and destabilized by a temperature contrast, is investigated when turbulence, produced by vertically oscillating horizontal grids, is imposed on the deeper layers above and below the interface. The fluxes of heat and salt are measured as functions of a non-dimensional parameter λ, which expresses the ratio of the grid-generated velocity to the convective velocity. Both fluxes were found to increase with λ For λ ⪡ 1 the double-diffusive convection process appeared to be the dominant transport mechanism and for λ ⪢ 1 mechanical mixing processes appeared to be dominant. The results were compared with those of Turner [1] which were obtained with only one diffusing component, and for the special case of salt flux the effectiveness of double-diffusive convection can be illustrated by examining the effect of changing the temperature difference between the layers.