光滑宽浅明渠流动垂线流速分布公式研究  

Study on generalized velocity distribution formula of flows in smooth wide open channel

作　　者：梁越[1] 曹叔尤[1] 杨奉广[1] 杨克君[1] 

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,成都610065

出　　处：《水力发电学报》2013年第5期147-152,共6页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金(51279116;51079090);教育部新教师基金(20120181120124)

摘　　要：对于宽浅光滑明渠流而言,目前工程上常用的是对数流速分布公式,但是对数公式在y+=u*y/ν=0处无意义,这一点在理论上是不合理的。本文从N-S方程入手推导出内区外区的流速导数公式,在此基础上给出了适用于整个水深范围内的流速导数公式,对其求积分得出了宽浅明渠流速分布统一公式并通过试验数据求出了公式中的未知参数。作者公式u+不仅是无因次水深y+的函数,而且也是y/h的函数,这一点与对数补偿公式相似。利用647组试验数据,将作者公式与现存的三家流速分布统一公式对比,发现作者模型计算精度最高。另外,对作者公式求导发现,当在y+=h+处,du+/dy+=0,满足极值定理,说明作者公式的结构比其它公式更合理。A widely used formula in engineering for velocity distribution of flows in smooth wide open channel is the log law, but it is unreasonable at the bottom y ＋ = 0. This paper presents a unified differential equation for the dimensionless velocity u ~ that is derived from the Reynolds-averaged Navier-Stokes equations and a unified formula of velocity distribution valid in the full depth range of smooth wide open channel. This formula relates u ＋ not only to y ＋ but also to dimensionless water depth 8 = y/h, a similar case to the wake law. Its velocity gradient at the water surface is zero and satisfies the axial symmetrical condition. Its parameters were determined from experimental data. To verify the new formula, 647 sets of experimental data were used and three generalized formulae were selected from the literature for comparison. The results show that the authors＇ formula gives the best prediction among the formulae and thus is recommended for engineering calculation of velocity distribution of flows in smooth wide open channel.

关 键 词：水力学 光滑宽浅明渠 流速分布 对数公式 极值定理 

分 类 号：TV131[水利工程—水力学及河流动力学]