矩形平底渠道淹没水跃区的紊流边界层发展  

Development of turbulent boundary layer in submerged hydraulic jump regions of rectangular flat bottom channels

作　　者：张志昌[1] 王学斌 傅铭焕 

机构地区：[1]西安理工大学水利水电学院,西安710048 [2]中国水电建设集团十五工程局有限公司第四工程公司,西安710065 [3]浙江省水利水电勘测设计院施概院,杭州310002

出　　处：《水力发电学报》2016年第12期77-85,共9页Journal of Hydroelectric Engineering

摘　　要：根据Rajaratnam对矩形平底渠道淹没水跃区的断面流速分布、最大流速、壁面切应力和最大流速之半处距壁面距离的试验成果,利用Verhoff的附壁射流区的断面流速分布公式和紊流边界层的动量积分方程,研究淹没水跃区紊流边界层的发展、最大流速之半处距壁面距离和水跃区零流速线的计算方法。给出了淹没水跃区最大流速沿程变化的近似计算公式;提出了紊流边界层厚度、最大流速之半处距壁面距离和零流速线的理论计算方法,通过Rajaratnam的试验资料对其进行了验证和修正,给出了实用的计算公式;完善了Rajaratnam最大流速之半处距壁面距离经验公式中系数的计算方法。研究表明,矩形平底渠道淹没水跃区紊流边界层的计算公式在形式上与一般光滑平板一样,与雷诺数1v x/?的1/5次方成反比,与距离x的1.14次方成正比,相对最大流速之半处距壁面距离和零流速线均与跃前断面雷诺数成反比,与相对距离成正比。Methods for determining the development of a turbulent boundary layer and its wall distances of half maximum velocity and zero-velocity line in submerged hydraulic jump regions are presented in this paper. To derive these methods, we have applied Verhoff＇s formula of local velocity distribution in wall jet regions and the momentum integral equation of turbulent boundary layers to a detailed analysis of Rajaratnam＇s experimental data： local velocity distribution, local maximum velocity, bed shear stress and the wall distance of half maximum velocity collected from the submerged hydraulic jump regions in a rectangular fiat-bottom channel. The analysis gives an approximate formula of maximum velocity distribution and theoretical formulae for calculating the thickness of a turbulent boundary layer and its wall distances of half maximum velocity and zero-velocity line. Using the measured data, we verified the new formulae and improved the coefficient in Rajaratnam＇s empirical equation for calculation of the wall distance of half maximum velocity. The results show that the development of a turbulent boundary layer in submerged hydraulic jump regions is rather similar to that in the smooth plate case： its thickness is proportional to the 1.14 powers of wall distance x and inversely proportional to the one fifth power of v1x / v. And the wall distances of half maximum velocity and zero-velocity line are proportional to x and inversely proportional to the Reynolds number at the initial section of the jump.

关 键 词：水力学 淹没水跃 流速分布 边界层 零流速线 

分 类 号：TV133[水利工程—水力学及河流动力学]