Large-eddy simulation of a particle-laden turbulent channel flow

Large-eddy simulations of a vertical turbulent channel flow with 420,000 solid particles are performed in order to get insight into fundamental aspects of a riser flow The question is addressed whether collisions between particles are important for the ow statistics. The turbulent channel ow corresponds to a particle volume fraction of 0.013 and a mass load ratio of 18, values that are relatively high compared to recent literature on large-eddy simulation of two-phase flows. In order to simulate this ow, we present a formulation of the equations for compressible ow in a porous medium including particle forces. These equations are solved with LES using a Taylor approximation of the dynamic subgrid-model. The results show that due to particle-fluid interactions the boundary layer becomes thinner, leading to a higher skin-friction coefficient. Important effects of the particle collisions are also observed, on the mean fluid prole, but even more o on particle properties. The collisions cause a less uniform particle concentration and considerably flatten the mean solids velocity prole