Abstract

Many natural and industrial processes involve the flow of solid particles or liquid droplets whose dynamical evolution are intimately coupled with a carrier gas. A peculiar behavior of such flows is their ability to give rise to large-scale structures (hundreds to thousands of times the size of individual particles), from dense clusters to nearly-particle-free voids. Seminal works by G.K. Batchelor has provided theoretical estimates describing the motion of collections of particles suspended in viscous flows and the notion of hindered settling under gravity. In this talk I will describe how at moderate Reynolds numbers and concentrations, momentum exchange between the phases results in enhanced settling and the generation of turbulence in the carrier phase. High-resolution simulations will be presented to reveal how multiphase interactions at the particle scale augment or restrict large-scale flow processes, and provide unique insight into the budget of turbulent kinetic energy. Finally, a new data-driven framework will be presented for model closure of the averaged two-phase flow equations.