title: Particle velocity distribution in saltation transport.
abstract: We report on wind-tunnel measurements of particle velocity distribution in aeolian transport. By performing extended statistics, we show that for saltation occurring over an erodible bed the vertical lift-off velocity distributions deviate significantly from a Gaussian law and exhibit a long tail accurately described by a lognormal law. In contrast, saltation over a rigid bed produces Gaussian velocity distributions. These results strongly suggest that the deviation from Gaussian distributions is a consequence of the splash process which is exclusively present in saltation transport over an erodible bed. We further suggest that the non-Gaussian statistics is intimately related to the statistical properties of a single splash event which produces ejection of particles with lift-off velocities distributed according to a lognormal law. This lognormal behavior can be simply inferred from the propagation process of the impact energy through the granular bed which can be viewed as the analog of a fragmentation process. These findings emphasize the crucial role of the splash process in saltation transport.
authors.affiliation: Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes 1, 35042 Rennes cedex, France.
authors.forename: T D
authors.initials: TD
authors.lastname: Ho
authors.forename: P
authors.initials: P
authors.lastname: Dupont
authors.forename: A
authors.initials: A
authors.lastname: Ould El Moctar
authors.forename: A
authors.initials: A
authors.lastname: Valance