A three-dimensional analysis on lift-off velocities of sand grains in wind-blown sand flux

作者：Zheng Xiaojing^*; Cheng Ning; Xie Li

来源：Earth Surface Processes and Landforms, 2008, 33(12): 1824-1838.

DOI：10.1002/esp.1740

• Wind-blown sand flux
• three-dimensional grain-bed collision model
• lateral velocity
• lateral angular velocity
• upward angular velocity

This paper focuses on a key problem in wind-blown sand transport research, the lift-off velocities of sand grains. A three-dimensional grain-bed collision model comprising an impact sand grain, a creeping sand grain and a sustaining grain is presented. Based on this model, the analytical formulae of sand grains' linear and angular velocities are derived. The rebound/ejected coefficient (ratio of rebound/ejected velocity to impact velocity) and angle are numerically calculated using the analytical formulae and they agree well with the experiment results, which indicates that the three-dimensional model is credible and necessary. Comparisons of our results with the results gained by a two-dimensional grain-bed collision model show that all components of both rebound and ejected velocities gained by the three-dimensional model are lower than the corresponding ones done by two-dimensional model apart from the horizontal rebound velocity. It also shows the lateral velocity and the lateral angular velocity, as well as the upward angular velocity, cannot be obtained by a two-dimensional model, and cannot be ignored when the impact velocity is high.

• 出版日期2008-10
• 单位兰州大学