泥沙起动流速研究

从泥沙起动的特点出发，将瞬时作用流速、起动标准、泥沙颗粒在床面的相对暴露度及附加质量力等影响因素同时引入到推移质泥沙起动中，使分析泥沙起动时考虑的因素更加全面。采用经典力学与统计理论相结合的方法，得到了泥沙起动无量刚切应力公式。并对公式中的系数进行了数值计算。结果表明，该系数并非为一个常数，而是在一定的范围内，且随床面上颗粒的相对暴露度而变。同时，还得到了概括散粒体和粘性细颗粒泥沙的统一的均匀沙起动流速公式的上、下限。说明其系数也是在一个区间取值。 关键词：泥沙；临界切应力；起动流速

Study on incipient velocity of sediment

The effects of instantaneous velocity,incipient standard,relative exposed extent and additional mass are considered simultaneously in analyzing the incipient of sediment on riverbed.Based on the combination of classical mechanics principle and statistic theory,a dimensionless formula for shear stress of sediment incipient is deduced.The coefficient in the formula is calculated. It is found that the coefficient is not a constant but locating in a range and is dependent on the relative exposed extent of sediment.Meanwhile,a universal formula of incipient velocity for uniform sediment both for discrete particle and cohesive particles is obtained.