动床沙粒阻力计算的研究

A Study on the Sand-grain Resistance in Movable Bed

沙粒阻力的计算是泥沙运动力学的重要问题。基于泥沙的起动阻力来研究沙粒阻力的计算,是一种较为直接的方法。利用泥沙起动的Shields曲线与明渠阻力特性之间的相似性,结合实测泥沙起动资料给出了沙粒阻力的计算公式。该公式表示的沙粒阻力系数仅是能坡的函数,从而避免了采用相对水深时床沙代表粒径选择的困难。验证结果表明,该公式要优于其他沙粒阻力的计算公式。

Computation of sand-grain resistance is one of the most important issues in sediment transport mechanics. It is proposed that computation of sand-grain resistance based on resistance of sediment incipient motion is a direct method. By use of the similarity between Shields diagram and open channel resistance, the equation of sand-grain resistance is derived by combining with measured incipient data. This equation shows that sand -grain resistance coefficient is only a function of energy slope, and independent of sediment diameter, so the difficult of selecting bed representative diameter. Verification results show that the equation proposed by this paper is super to other sand - grain resistance equations.