Inertial particles in a turbulent/turbulent interface

Over the last three decades, the main advances in the understanding of particle-turbulence interactions have come from the study of a canonical flow: homogeneous isotropic turbulence. However, most flows in nature feature non-homogeneous turbulence with a turbulent interface separating two regions of different turbulent intensities (turbulent/non-turbulent or turbulent/turbulent). Although there are several studies on the dispersion of inertial particles in free-shear flows, few experiments have focused on the entrainment of particles by a turbulent interface. In the present study, we present the effect of a sheared turbulent/turbulent interface on the particles' clustering properties and settling velocity modification. With wind tunnel experiments, a high gradient of turbulence intensity is introduced in the sheared turbulent flow collocated with the particle injection. Particles are transported from the turbulent side, with higher turbulence intensity, to the low-intensity side by large-scale-energetic eddies. The physics of entrainment in the T/T interface also result in an enhancement of particle preferential concentration and settling velocity, consistent with the extended interaction of those particles with turbulent structures across the entire turbulent spectrum.