Exploring the dynamics of turbulence suppression due to dispersed phase in various geophysical flows*

Geophysical flows that are characterized as multiphase and turbulent, the feedback of dispersed phase tends to alter the carrier phase turbulence and degree of isotropy. In turbidity currents, suspended sediments sustain turbulence by driving the flow and at the same time can kill the flow by suppressing turbulence through stratification effects. Similarly in hurricanes, the intensity of wind can be modulated by the stratification effects of water droplets that are injected into it by sea-sprays. To study such flows, we implemented models with dilute suspensions and performed DNS at moderate Reynolds numbers. These studies show that there are three governing parameters: Reynolds number, Richardson number and size of the dispersed phase particles. Parametric groupings that quantify turbulence suppression were identified for these flows. We have also looked into the interaction of wave induced turbulence and its ability to transport fine sediments. Here we will present the mechanism that is responsible for modulating the near wall vortical structures that can potentially explain the loss of turbulence in turbidity currents, fluctuations in the carry capacity of wave induced sediment transport and drag saturation of hurricane intensity winds due to sea-sprays.