The effect of a curved bed on the discharge equation in a spillway with a breast wall  

作　　者：NGUYEN Cong-Thanh 王玲玲 唐洪武 

机构地区：[1]State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,College of Water Conservancy and Hydropower Engineering, Hohai University

出　　处：《Journal of Hydrodynamics》2015年第2期311-318,共8页水动力学研究与进展B辑（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.51179058,51479058);the State key program of National Science Fund of China(Grant No.51239003);the Special Fund for Public Welfare of Water Resources Ministry(Grant No.201201017);the 111 Project(Grant No.B12032)

摘　　要：The flow through a breast wall spillway is greatly affected by the centripetal force due to a downstream curved profile. Therefore, the mean vertical pressure distribution at the outlet section is not consistent with the hydrostatic pressure law. This distribution in turn affects the discharge capacity of the breast wall spillway. This paper experimentally studies the effect of a convex downstream profile on the mean pressure variation and the discharge of a breast wall spillway without gates. It is indicated that the effect of the curvilinear streamline on the mean vertical pressure variation is significant. The regression analysis method is used to determine the water head effect Z o of the orifice opening through the mean pressure variation. A discharge prediction formula of the breast wall spillway is obtained under the limited conditions of a laboratory flume. The predicted discharge is compared to the measured discharge. A good agreement is evidenced for the free orifice flow with errors within ？5%, while a big error（20% or even more） is obtained if the hydrostatic pressure law is used for the determination of Zo.The flow through a breast wall spillway is greatly affected by the centripetal force due to a downstream curved profile. Therefore, the mean vertical pressure distribution at the outlet section is not consistent with the hydrostatic pressure law. This distribution in turn affects the discharge capacity of the breast wall spillway. This paper experimentally studies the effect of a convex downstream profile on the mean pressure variation and the discharge of a breast wall spillway without gates. It is indicated that the effect of the curvilinear streamline on the mean vertical pressure variation is significant. The regression analysis method is used to determine the water head effect Z o of the orifice opening through the mean pressure variation. A discharge prediction formula of the breast wall spillway is obtained under the limited conditions of a laboratory flume. The predicted discharge is compared to the measured discharge. A good agreement is evidenced for the free orifice flow with errors within ？5%, while a big error（20% or even more） is obtained if the hydrostatic pressure law is used for the determination of Zo.

关 键 词：curved bed SPILLWAY breast wall multiple linear regression orifice flow mean pressure distribution 

分 类 号：TV651.1[水利工程—水利水电工程] TV135.2