Inertial particle dynamics across flows, from channel turbulence to impinging jets
Small and heavy particles dispersed in flows are prevalent in environmental and industrial processes, and they also play a key role to space exploration and vehicle operations in dusty environments. In this talk we will discuss ongoing efforts on particle laden flows on two distinct flow configurations. Both efforts share the motivation of understanding the flow physics and developing and validating models that aid their prediction. The first part will focus on preferential concentration of small inertial particles by channel turbulence and the dynamics of particle clusters. We will present a new vertical particle-laden channel flow facility with a total length of 225 times the channel width and discuss recent results from high-speed planar imaging on particle cluster size, local concentration conditioned velocities, and lifetime statistics. Test conditions to date include varying Reynolds numbers, effectively varying the particle Stokes number based on the dissipative scale from 10 to 50 for the same particle time constant, and varying particle volume loading, from highly to moderately dilute, at which two-way coupling and turbulent modulation are expected. The second part of the talk will cover ongoing work on plume granular surface interactions. We focus on the high surface erosion rate regimes produced by a supersonic jet impinging on a bed of 109-micron diameter glass particles, and on the dense clouds of ejecta particles generated. Several diagnostics are combined to probe the unladen flow, the particle cloud and the crater formed by the jet, and to reconstruct the 4D ejecta evolution and estimate erosion rates..
Contact Nathanaël Machicoane for more information or to schedule a discussion with the seminar speaker.