Simple Stochastic Model for Particle Dispersion Including Inertia, Trajectory-Crossing, and Continuity Effects

Abstract

An eddy-lifetime, stochastic Lagrangian model for particle dispersion in weakly laden turbulent flows is proposed, in which the interaction time-scale between particles and turbulent eddies is parametrized so as to include several physical effects. It takes into account particle inertia, crossing-trajectory effect, the possible difference in lateral and longitudinal dispersion, and some Reynolds number effects. The parametrization is based on previous results, from a theoretical dispersion model in isotropic turbulence using the trajectory-velocity independence and Gaussian approximations, as well as from Large-Eddy-Simulation. Simple fits are introduced to efficiently capture the main results from these prior studies, allowing practical implementation within the context of k – ε engineering codes. Results from simulations using the proposed approach are compared with experimental data of dispersion in decaying isotropic turbulence.