矩形明渠自由水跃长度的理论分析

Theoretical analysis on the length of free hydraulic jump in rectangular open channel

通过分析前人对矩形渠道平底自由水跃长度的研究成果,根据Rajaratnam对附壁射流、水跃区最大流速分布和壁面切应力的试验成果,采用紊流边界层的动量积分方程,研究了矩形渠道自由水跃区边界层的发展和水跃长度的理论计算方法,得出了水跃区边界层发展和自由水跃长度的计算公式,通过实例验证了公式的适用性。本文提出的水跃长度的理论计算方法对矩形明渠自由水跃长度的研究有启示和借鉴作用。

This paper presents two theoretical formulas, one for calculation of boundary layer development in the region of free hydraulic jump in a rectangular open channel, and the other for calculation of the jump length. These formulas were derived from the momentum integral equation of turbulent boundary layer and an analysis of the similar results in the previous studies and Rajaratnam＇ s experimental results of hydraulic jump, including adhesive wall jet flow, maximum velocity distribution and wall shear stress formula. The applicability of the formulas was verified by example calculations. The method and formulas lend a support to the study of free hydraulic jump length in rectangular open channel.