Convective instability-induced mixing and its parameterization using large eddy simulation

Abstract

Abstract A large eddy simulation (LES) model is applied to study convective instability processes driven by hydrothermal exhalations. The process of convective mixing induced by a bottom heating source is examined in a stratified and rotating frame. The control case of numerical experiment is configured with the horizontal and vertical resolution 5\u202fm located at 35°S. Its results show that the three-dimensional structure of the hydrothermal plume displays an umbrella shape. A strong clockwise vortex above the vent is present and the axis of the vortex is tilted with organized precession. A series of numerical experiments are conducted to test the sensitivity of three characteristic parameters (eddy viscosity (K), maximum plume rise height (Zmax) and the intensity of the vortex (Ivortex)) to three variables: heat flux from the vent (HF), rotation rate (f) and background stratification (N). Based on the sensitivity experiments, parameterizations of eddy viscosity and maximum plume rise height with respect to HF, f and N are obtained.