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基于白玉川提出的床面均匀无黏性泥沙双向相对暴露度、拖曳力系数、上举力系数与纵向相对暴露度之间的关系分析发现,当颗粒雷诺数较大时(大于15 700),拖曳力系数、上举力系数仅受相对暴露度影响,且幅值变化较小.CD取值在1~1.22,平均值为1.11;CL取值在0.72~0.99,均值0.86.将拖曳力系数和上举力系数引用到泥沙起动流速公式的研究中,推导出基于相对暴露度的散粒体泥沙起动底部作用流速公式及垂线平均流速公式,通过与现有的天然河道、室内水槽试验得到的泥沙起动流速资料及现有的泥沙起动流速公式比较可知,本文公式与实测资料符合良好,较现有的泥沙起动公式计算精度更高.
Based on the analysis of the relationship between the two-way relative inhomogeneity, drag coefficient, uplift coefficient and longitudinal relative exposure of the homogeneous and non-viscous sediment in bed by Bai Yuchuan, it is found that when the Reynolds number is larger (more than 15 700) , The drag coefficient, the lift coefficient is only affected by the relative exposure, and the amplitude change is small.CD value of 1 ~ 1.22, the average value of 1.11; CL value of 0.72 ~ 0.99, mean 0.86. Drag the drag Coefficient and uplift coefficient are used to study the formula of sediment flow velocity, and the formula of sediment bottom flow velocity and vertical average flow velocity based on relative degree of exposure are deduced. By comparing with the existing natural channel, indoor It can be seen from the comparison between the sediment flow velocity data obtained from the tank test and the existing sediment flow velocity formula that the formula in this paper is in good agreement with the measured data and is more accurate than the existing sediment onset formula.