Shear Effects on Buoyancy-Generated Turbulence and Salt Fingers

Abstract

Linear theory and laboratory experiments on a finger-favorable gravity current are applied to study turbulence in a salt finger favorable flow. The theory reproduces well previous observations for unsheared flow, and it predicts that heat can be transported more efficiently than salt, even in salt finger favorable conditions. Effects of shear on the flux ratio are small. The laboratory experiment also produces results similar to the linear theory. Even though the bulk mixing rate increases as the density ratio decreases, the heat flux is larger than the salt flux, and no strong signature of salt fingers was detected. Eddy diffusivities are estimated from control volume analysis and oceanographic microstructure methods.