一、前言一般常用古典公式计算水跃的消能率,由于低佛氏数水跃跃后流速分布不均匀,而且紊动剧烈,导致了消能率过高的假象,造成了水跃下游河床的严重冲刷,甚至造成工程失事。如内蒙河套灌区63个闸,除13个是缓流连接外,其余50个闸佛氏数都在1.7—3.5之间,但闸年冲刷却十分严重,有的冲刷深度达4米,两岸掏刷达30米,严重影响了工程的安全。近几下来,人们对低佛氏数水跃特性的研究才重视起来。虽然有人指出在低佛氏数水跃计算中,流速分布的不均匀性及紊动能是不能忽略的重要 I. Introduction Generally, the classical formula is used to calculate the energy dissipation rate of water jets. Due to the non-uniform flow velocity and the strong turbulence after low water jump, the illusion that the energy dissipation rate is too high is caused, resulting in serious river bed downstream of water jets Scouring, and even caused a crash. For example, in Inner Mongolia Hetao irrigation area 63 gates, in addition to 13 slow connection, the remaining 50 gate Buddha number are between 1.7-3.5, but the gate erosion is very serious, and some erosion depth of 4 meters, cross-strait dig Brush up to 30 meters, seriously affecting the safety of the project. In recent years, attention has been paid to the study of the low Vodafone hydrodynamic characteristics. Although it has been pointed out that in low-Foyer hydrodynamic calculations, the inhomogeneity of the velocity distribution and the turbulence energy can not be neglected