矩形断面明渠中恒定均匀流的机械能损失  

Mechanical energy loss of steady uniform flow in rectangular open channels

作　　者：范敏[1] 王菁 刘士和[1] 

机构地区：[1]武汉大学水利水电学院,湖北武汉430072 [2]长江勘测规划设计研究有限责任公司,湖北武汉430015

出　　处：《武汉大学学报（工学版）》2015年第1期15-19,26,共6页Engineering Journal of Wuhan University

基　　金：水利部公益性行业科技专项经费(编号:201101005)

摘　　要：明渠流中机械能损失的确定是水力学乃至工程流体力学中的重要内容.以构建的明渠恒定流新的总流能量方程及矩形断面明渠三维层流运动的理论解为基础,通过理论分析与三维数值计算,就矩形断面明渠中恒定均匀流的机械能损失系数随雷诺数及宽深比的变化进行了深化研究,得到如下成果:1)在层流条件下,机械能损失系数一般均与雷诺数和宽深比有关,只有对宽深比大于6.5的宽浅明渠,其相应流动的机械能损失系数才仅与雷诺数有关,且在雷诺数相同的条件下,一般矩形断面明渠流的机械能损失系数要大于宽浅明渠流的机械能损失系数;2)在紊流条件下,机械能损失系数也一般均随雷诺数与宽深比而变,但对给定的宽深比,存在相应的特征雷诺数,当流动的实际雷诺数大于该特征雷诺数后,机械能损失系数则不再随宽深比而变化,且在宽深比一定的条件下,雷诺数越小,其机械能损失系数的修正值越大.The calculation of mechanical energy loss of flow in rectangular open channel is an important part both in hydraulics and fluid mechanics. In this paper the variation of mechanical energy loss with Reynolds number and wide-depth ratio is further investigated by theoretical analysis and three-dimensional numerical simulation based on the new energy equation for steady channel flow and the theoretical solution of the ve- locity field for laminar flow in a rectangular open channel. The results are as follows： 1） Under laminar flow conditions, the mechanical energy loss coefficient varied generally with Reynolds number and the wide-depth ratio of channel. When the wide-depth ratio is greater than 6.5, the mechanical energy loss co- efficient only varied with Reynolds number. The mechanical energy loss coefficients in ordinary rectangular open channels are greater than those in wide-shallow open channel of the same Reynolds number. 2） Under turbulent flow conditions, the mechanical energy loss coefficient also varied with Reynolds number and the wide-depth ratio. For the given wide-depth ratio, there exists the corresponding Reynolds number that the mechanical energy loss coefficient is unchanged with varied wide-depth ratio when Reynolds number is greater than the corresponding Reynolds number and the mechanical energy loss coefficient decreases with the increasing of Reynolds number.

关 键 词：矩形明渠 机械能损失构成 层流 紊流 

分 类 号：TV133.1[水利工程—水力学及河流动力学]