Author(s)

C. Aguirre, S. Simoens & M. Ayrault

Abstract

Prediction of solid heavy particle dispersion in turbulent flows requires the knowledge of the fluid velocity seen by the solid particle. A one particle and one time scale lagrangian stochastic model has been developed for the determination of the driving fluid velocity. A modified time correlation taking into account the effects of gravity and inertia is used. We focus on the grain trajectories of saltating particles whose volumetric mass are much greater than that of the fluid (pp / pf > 103). A comparison with wind tunnel experiments run by Snyder and Lumley [5] is made. The good agreement of the numerical results with experimental data demonstrates that the eolian transport must be considered as a stochastic process. This approach is promising and quite well adapted for the modelisation of eolian saltating particles. 1 Introduction Dust produced by wind erosion is a major source of atmospheric aerosols. On the basis of wind-tunnel observations [1], it has been found that saltation bombardment appears to be mainly responsible to dust emission. During an erosion event, saltation can move large quantities of soil over distances from meters to kilometers. In the process, the soil is winnowed of its finer particles. These small particles become suspended in the air as dust, and can be dispersed away from the surface by atmospheric turbulence and finally transported over very large distances. So, the study of the dispersion of

Keywords