沙粒斜碰的动力特性分析

Analysis on dynamic characteristics of the inclined impact between sand particles

利用动力学中的碰撞理论 ,根据沙粒斜碰的简化模型 ,得到了跃移沙粒与床面上的单个蠕移沙粒碰撞后两碰撞沙粒的速度与角速度的解析表达式 .床面沙粒能否被激发离开床面主要与入射沙粒的入射速度的方向、两碰撞沙粒接触的方位角以及床面上沙粒的蠕移速度相关联 .即 :蠕移速度越大 ,其沙粒越容易被激发离开床面 .

Based on the impact theory in dynamics and using the impact model between the sand particles,this paper presents analytical solutions of the velocity and angular velocity of sand grains after a sand grain in saltation moves down to the sand bed and the moving sand particle impacts with one creeping sand grain on the sand bed. The quantitative results show that whether or not a sand grain on the sand bed is ejected off the sand bed is mainly depend upon the direction of the velocity of the moving sand particle in saltation,the azimuth angle of the connected particles and the velocity of sand creep on sand bed. That is,the larger the velocity of sand creep,the easier the sand is ejected off the sand bed. Finally ,a simulation for the path of rebound and ejected sand particles into saltation is conducted based on the impact analysis.