Estimating the coefficient of discharge from the sluice and radial gates

In this paper, the characteristics of free and submerged outflow from the sluice and radial gates were studied by using energy and momentum equations, and experimental data of other researchers. An equation has been given to approximate the energy loss of the gate along with its application in improving the accuracy of the discharge coefficient under free flow condition has been demonstrated. A theoretical equation is also developed for estimating the discharge coefficient of sluice gates and three types of radial gates, namely Hard-Rubber, Music Note, and Sharp, under submerged flow condition. It was observed that at a certain condition, the outflow from Hard-Rubber type radial gate is larger than Music Note and Sharp types. It was realized that the mean energy loss of these types of radial gates, under submerged flow condition, is dependent on the ratio of the axial height of the gate to its radius which was used to improve the discharge coefficient. Under a certain condition, it was observed that, the discharge coefficient would decrease if the angle of gate lip is increased. It was also observed that under certain circumstances, the outflow from three types of radial gates, is much larger than sluice gates. It is noteworthy to mention that the application of the developed equation for estimating the discharge coefficient of the Sharp radial gate for Hard-Rubber and Music Note types may cause considerable errors.