INTERFACIAL FLUXES AT A GRID-STIRRED DIFFUSIVE INTERFACE

Results from a grid-mixing experiment in a diffusive thermohaline syst em are described. A model is proposed to separate the effects of inter facial flux and interfacial movement (entrainment) on property changes in the mixed layer and the present results for heat and salt fluxes a re compared with previous studies in unstirred diffusive systems. Comp arison of an eddy time-scale and a time-scale for development of insta bility in the interfacial boundary layers suggests a means of determin ing whether stirring or double-diffusive instability controls the inte rfacial transports. For the present conditions there was a negligible effect of diffusive stratification on entrainment rates, and interfaci al fluxes were increased by the stirring. It is suggested that the rat io R(F)/R(rho), where R(F) is the interfacial flux ratio and R(rho) is the interfacial stability ratio, should be a function of the overall bulk Richardson number, Ri.