【摘要】 阐述了砾卵石均匀沙的运动机理,通过对附加质量力和床面颗粒相对暴露度参数的引入,推得了均匀沙起动无因次拖曳力公式,并对公式中的系数进行了计算。结果表明,在起动状态一定时,该系数并非为一个常量,而是介于某个区间,且随颗粒在床面上的相对暴露度的变化而变。通过转化推得了散粒体均匀沙起动流速公式,同时考虑了砾卵石扁度的影响,其系数同样不是一个常量,同学者们的公式相对照较为合理,该系数包含了其它公式的系数。结论部分可以解释为何不同的作者通过实验所拟合的系数各异,且差别较大,说明文中公式基本能反映均匀沙的起动特性。更多还原

【Abstract】 In this paper , the motion mechanism of uniform sediment is presented . By introducing the additional mass force and the relative exposure degree of grain on riverbed , the formula of dimensionless traction force for starting uniform sediment is established and coefficient in the formula is calculated . The calculation result indicates that for a given starting condition , the coefficient is not a constant , but varies with the relative exposure degree of grain . The formula of starting velocity of uniform sediment is derived and influence of gravel flatness is also considered .Its coefficient is not a constant . It is explained in conclusion that why do the coefficients gained by various authors are quite different . The formula can basically show the starting motion characteristics of uniform sediment.更多还原