Patterns, Transport, and Anisotropy of Salt Fingers in Shear

Abstract Through an expansive series of simulations, we investigate the effects of spatially uniform shear on the transport, structure, and dynamics of salt fingers. The simulations reveal that shear adversely affects the heat and salt fluxes of the system, reducing them by up to an order of magnitude. We characterize this in detail across a broad range of Richardson numbers and density ratios. We demonstrate that the density ratio is strongly related to the amount of shear required to disrupt fingers with larger density ratio systems being more susceptible to disruption. An empirical relationship is proposed that captures this behavior that could be implemented into global ocean models. The results of these simulations accurately reproduce the microstructure measurements from NATRE observations. This work suggests that typical salt finger fluxes in the ocean will likely be a factor of 2–3 less than predicted by models not taking the effects of shear on double-diffusive systems into account.