Two regimes of dilute turbulent settling suspensions under shear

When turbulent flow is laden with negatively buoyant particles, their mean distribution in the direction of gravity can induce stable density gradients that penalize turbulent fluctuations. This effect is studied numerically for shear-driven flow with dilute noninertial sediment. The turbulent dynamics and sediment transport depend critically on particle settling velocity vs, splitting into two regimes: homogeneous weakly stratified turbulence and flow with developed turbulence atop an intermittent boundary layer. At intermediate vs, neither state can be sustained and the flow laminarizes. Published by the American Physical Society 2024