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

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 m 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 ( Z max ) and the intensity of the vortex ( I vortex )) 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.