均匀沙起动流速研究

Study on incipient velocity of uniform sand

从均匀沙起动的特点出发 ,阐述了其运动机理 ,分析泥沙颗粒受力时 ,除考虑拖曳力、上举力和水下重力外 ,还应考虑由于颗粒相对暴露度而产生的附加质量力。验算表明 ,提出的附加质量力的概念及其表达式是合理的。采用滚动起动模式 ,通过对附加质量力的概念及表达式和相对暴露度参数的引入 ,推得了均匀沙起动公式 ,并用实测资料进行了验证 ,同其它学者们的公式相比较为合理 ,该系数包含了其它公式。同时还得到了包括粘性沙在内的均匀沙的起动流速公式 。

The motion mechanism of uniform sand is presented in view of its incipient characteristics.In the light of rolling incipient mode and introducing the concept and formula of additional mass force and index of relative exposure degree,the calculation formula of incipient velocity of uniform sand is established and verified by measured data,which is more reasonable than the formulas suggested by other scholars,its coefficients include other formulas'.In the meantime,the formula of incipient velocity of uniform sand taking viscosity into account is also establised.The formulas in this paper fundamentally reflect the incipient characteristics of uniform sand.