Properties of the particle velocity field in gas-solid turbulent channel flow

Spatial characteristics of the particle velocity field are investigated using numerical simulations of gas-solid turbulent channel flow. The carrier phase is resolved using large eddy simulation (LES) of the incompressible Navier-Stokes equations. The dispersed phase is computed using Lagrangian tracking in which particle motion is governed by the drag force. Predictions of dispersed phase transport are obtained for three particle response times in simulations with and without interparticle collisions. Spatial correlations of the particle velocity field are measured in planes parallel to the wall and exhibit a discontinuity at the origin. The discontinuity in the spatial correlations is consistent with recent work by Fevrier [J. Fluid Mech., 533, 1 (2005)] that shows the velocity of a particle is comprised of a contribution from a continuous field, shared by all the particles, and a random velocity component that is not spatially correlated. Analysis of the simulation database shows that the random component of the particle velocity increases with increasing particle response time. The influence of interparticle collisions leads to a changes in the partitioning of the particle velocity, with a greater fraction residing in the uncorrelated component compared to the correlated part.