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Updated: May 11, 2026

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
Influence of sand grain diameter and wind velocity on lift-off velocities of sand particles
Tian-Li Bo1, Xiao-Jing Zheng, Shao-Zhen Duan
1Key Laboratory of Mechanics on Western Disaster and Environment, Lanzhou University, 730000, Lanzhou. China, btl@lzu.edu.cn
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.
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