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A STOCHASTIC MODEL FOR THE EOLIAN SALTATION AND SUSPENSION TRANSPORT

Ivana Vinkovic
Laboratoire de Mécanique des Fluides et d'Acoustique, Université de Lyon, Université Claude Bernard Lyon 1, Ecole Centrale de Lyon, INSA de Lyon, CNRS UMR 5509, 36 Avenue Guy de Collongue, F-69134 Ecully, France

Michel Ayrault
LMFA, UMR CNRS 5509 Ecole Centrale de Lyon 69131 Ecully Cedex, France

Yu Guo
Turbulence Research Laboratory, Tsinghua University Beijing, China, 100084

Guixiang Cui
Department of Engineering Mechanics, Tsinghua University, Beijing, China 100084

Zaoshun Zhang
Turbulence Research Laboratory, Tsinghua University Beijing, China, 100084

Sinopsis

A model for the simulation of the transport of heavy particles by a turbulent boundary layer is established. The resolution of the lagrangian equation of the solid particle motion (in suspension or saltation) requires the knowledge of the instantaneous velocity of the surrounding fluid. This velocity is determined by a continuous stochastic equation. An appropriate lagrangian correlation timescale is considered in order to include the influences of gravity and inertia of the solid particle. The model consists of the aerodynamic entrainment of particles by the turbulent structures of the flow, the computation of the decorrelation between the solid and the fluid trajectories, the determination of the driving fluid velocity along the particle trajectory, the computation of the particle trajectory, the impact of grains on the bed and the estimate of new ejected sand or dust particles (splash function). Comparisons of the results from our simulation with different wind tunnel experiments are in a good agreement.