Interaction between particle clusters and particle-induced turbulence

To investigate the two-way interaction between particles and fluid turbulence, a homogeneous flow field including solid particles was numerically simulated, Spherical particles are falling by gravity with the Reynolds number ranging from 50 to 400, based on slip velocity. Particular attention was focused on the clustering of particles, which might enhance turbulence by energy supply through larger scales in comparison with dispersed particles. In the higher Reynolds number case, particle clusters are formed due to the wake, and vortex shedding enhances them. But clusters cause fluid turbulence resulting in their break-up. The Reynolds-number dependence, the dynamics and the time scale of particle clusters are discussed in this paper. (C) 2002 Elsevier Science Inc. All rights reserved.