Eur. Phys. J. E (2013) 36: 50
https://doi.org/10.1140/epje/i2013-13050-y

Regular Article

Influence of sand grain diameter and wind velocity on lift-off velocities of sand particles

¹⁹⁸⁶⁴ Key Laboratory of Mechanics on Western Disaster and Environment, Lanzhou University, 730000, Lanzhou, China
²⁹⁸⁶⁴ Department of Mechanics, Lanzhou University, 730000, Lanzhou, China
³⁹⁸⁶⁴ School of Electronical and Mechanical Engineering, Xidian University, 710071, Xi’an, China

^* e-mail: btl@lzu.edu.cn

Received: 17 November 2012
Accepted: 22 April 2013
Published online: 24 May 2013

Abstract

In this paper, the velocities of sand particles near the sand bed in the saltation cloud were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system. The influences of the diameter of sand particles in the saltation cloud and wind velocity on the probability distribution function (PDF) of lift-off velocities of sand particles were investigated. Results demonstrate that for the sand particles saltating above the sand bed with the mean grain diameter (d _m = 0.3 mm), smaller and larger ones have the same velocity distribution, and wind velocity has no obvious influence on the distribution shape of the lift-off velocities, i.e., the PDFs of the horizontal and vertical lift-off velocities both follow a lognormal distribution, but the diameter of sand particles in the saltation cloud and wind velocity have an influence on the parameters of the PDF of horizontal and vertical lift-off velocities. Eventually, we present formulas to describe the PDF of lift-off velocities of sand particles with regard to the influence of wind velocity and the diameter of sand particles in the saltation cloud above the sand bed with d _m = 0.3 mm.