1 Fluid-particle Correlated Motion and Turbulent Energy Transfer in a Two- dimensional Particle-laden Shear Flow

Discrete Vortex Simulations of a dilute two-dimensional particle-laden shear layer with one-way coupling were performed to study fluid-particle correlated motion and the transfer of turbulent kinetic energy between the phases. The resulting modification of carrier phase turbulence, estimated according to current computational models, was evaluated. Particle Stokes numbers were between 1.0 and 4.5, so that the particles showed considerable temporal concentration fluctuations due to centrifuging by the fluid flow structures, and the mass loading was 12 % corresponding to a volume fraction of 6.0⋅10-5. Fluid velocities and particle concentration and velocities and their covariances, which appear in a commonly used model equation for carrier phase turbulence modification, were evaluated. Additionally, the probability density functions of fluid velocity fluctuations viewed by the particles are presented and compared with their Eulerian counterparts. It was found that particles view reduced velocity fluctuations due to preferential clustering. The model for carrier-phase turbulence 2 modification predicted turbulence reduction, depending on the particle Stokes number. Th