Prediction of particle dispersion in turbulent flows

A model of particle behavior in turbulent flows is presented. Each particle trajectory is computed by numerically integrating the particle governing equations, with a random sampling to determine the instantaneous fluid velocity experienced by each particle. To take into account spatial and temporal structures of the turbulence, fluid domains are simultaneously tracked; their sizes and lifetimes are connected with length and time scales of turbulence. A particle can follow a fluid domain, or can move from one to one another (crossing trajectories effect). The presence of particles is assumed not to alter turbulent structures. Particle dispersion is determined from a sample of computed trajectories. Predictions agree favorably with experimental data for the grid-generated turbulence.