Sluice‐Gate Discharge Equations

Sluice‐gate discharge coefficient is an involved function of geometric and hydraulic parameters. For free flow, it is related to upstream depth and gate opening, whereas for submerged flow, in addition to these parameters, it depends on tail‐water depth. The present practice of discharge coefficient determination is from curves drawn relating discharge coefficient and upstream‐depth gate‐opening ratio with tail‐water‐depth gate‐opening ratio being the third parameter for submerged flow. This method lends itself to sufficient error of judgment due to interpolation between two types of curves. Furthermore, the graphical information cannot be used for any analytical and/or numerical method for flow control and flow profile determination. In this paper high‐accuracy discharge coefficient equations for free and submerged flows have been developed along with the criterion for determination of free and submerged flow. Procedures for solution of various gate‐opening problems have also been given.