冲积河弯水流结构及床面切力计算

Computation of Flow Structure and Boundary Shear Stress in Alluvial Bends

本文针对弯道环流一般均处于非充分发展状态这一具有普遍性的问题,从水流运动基本方程出发,建立了冲积河弯水流纵向垂线平均流速平面分布的理论公式。又据该式和文献[11]提出的弯道横向流速分布公式,对非充分发展的弯道水流结构及其演变规律进行了较全面的分析和探讨,提出一些新的见解,并进一步导出环流非充分发展弯道中纵向和横向床面切力计算公式。与已有的研究成果相比,本文提出的公式结构上更为合理和严谨,经实测资料验证,结果令人满意。

In this paper, based on the basic equation of motion,a theoretical depthaveraged longitudinal velocity equation which is directed against the general problem of spiral motion being usually nonfully developed in nature alluvial river bends has been derived. According to both the longitudinal velocity equation and the transverse velocity equation given by reference[11], the flow structure with nonfully developed spiral motion as well as the rule of the flow evolution in curved channel has been extensively investigated, and then, the two equations of longitudinal and transverse shear stresses on the bed of a bend are also derived. The structure of all three equations presented in this paper is not only more rational but also more rigorous than these of existing formulae. By comparison, the conclusion is reached: the results,which are calculated by foregoing equations and measured by lab as well as field data, are satisfactory.