On the Discharge Coefficient of Overflow Spillways

As maximum utilization of water resource is required, so increase the demand for the greater accuracy of discharge coefficient of overflow spillways. It is one of difficulty to reduce the general expression of discharge coefficient of overflow spillways that experimental data of dam model which involves effects of ratio of overflow depth to dam height, overflow depth to overflow span length and etc. It is necessary to establish the discharge coefficient of two dimensional overflow spillways, as a clue to elucidate the general expression of discharge coefficient of overflow spillways. The purpose of this study is to deduce the general expression of discharge coefficient of two dimensional overflow spillways. In this report, the author proposed the method to determine the control section and discharge coefficient of overflow spillways with general shape. In theoretical analysis, the author introduced the development of boundary layer along a surface of overflow spillways in the theory as to two dimensional potential flows as is generally known. We confirm that the achievements in this report are reasonable, in comparing with many former equation for discharge coefficient depend more or less on experimental data under various condition.