改进的突然对称扩散水跃方程

泄水建筑物下游的消能防冲是水利工程设计的重要问题。突然对称扩散水跃是消能的一种基本形式。为了研究突然对称扩散水跃共轭水深的水力特性，根据动量原理建立了突然对称扩散水跃共轭水深方程。发现突然对称扩散水跃始端扩散断面的回流平均水深ｈ３可以表示为跃前断面水深ｈ１和跃后断面水深ｈ２的函数，即ｈ３＝ｈ１＋αｈ２。根据大量实验资料，给出了系数α随着突扩比β变化的函数关系式。本文建议的方程能够很好的与实验吻合一致。在已有的计算方法中，本文方程与实验结果的平均误差和最大误差最小。因此，本文方程可以应用到实际问题的水力计算。

Improved Hydraulic Jump Equation in Abruptly Symmetrical Expanding Channel

Energy dissipation and scour prevention in downstream of outlet structure is an important issue in hydraulic engineering design. Hydraulic jump in abruptly symmetrical expanding channel is one of the basic forms of energy dissipation. In order to analyze the hydraulic characteristics of conjugate water depth of hydraulic jump in abruptly symmetrical expanding channel, the conjugate water depth equation of hydraulic jump in abruptly symmetrical expanding channel is derived according to the momentum principle. It is found that the average water depth in the backflow zone of the expanding section at the beginning of hydraulic jump in abruptly symmetrical expanding channel can be expressed as a function of the depths before and after a hydraulic jump, which is h3=h1+αh2. Based on a large number of experimental data, the formula of coefficient α varying with abrupt expansion ratio β is derived. The equation proposed in this paper agrees well with the experiment. In the existing calculation methods, the average error and the maximum error between the equation given in this paper and the experimental results are minimum. Therefore, the equation proposed in this paper can be applied to compute the engineering problem.