三元流作用下斜坡上散粒体泥沙起动条件探讨

Discussion on incipient condition of a noncohesive sediment particle on slope under 3D flow

泥沙起动规律的研究在理论分析上和实际应用中均具有重大意义。通过对斜坡上单颗粒散粒体泥沙进行三维受力分析,从理论上建立了包含有相对速度及脉动速度的泥沙颗粒滑动起动模型,直接量化了相对速度及脉动速度对单颗粒泥沙起动的影响,进而得到了斜坡上泥沙颗粒滑动起动条件及跃移条件。讨论了不同主流方向条件下相对速度及脉动速度的大小,得到了泥沙加速度公式,直观地反映了泥沙颗粒运动速度与加速度的相互影响、相互制约的关系。

The study of sediment incipient motion is of great significance both in theory and practice.The forces on a single and noncohesive sediment particle on the slope under 3D flow is analyzed,and the sediment sliding incipient model is established,which is able to analyze the effect of the relative velocity and fluctuating velocity on sediment incipient motion directly.The sliding incipient condition and jumping condition of nonco hesive sediment on the slope are obtained.The magnitudes of relative velocity and fluctuating velocity are discussed under the condition of different mainstream directions,and the formula of acceleration is also got,which can directly reflect the relationship between velocity and acceleration.