Self-Similarity Theory and relationships to determine discharge of sluice gates with cylindrical edge in free flow and submerged

Gates are among the most common hydraulic structures in open channels that are used for flow control and water level control. The vertical slide gates suffer from lower contraction coefficient and thus lower flow rate capacity. In this paper, the hydraulic performance of a new modified gate, combination of a vertical slide gate with a cylindrical edge (Drum gate), has been studied. The dimensionless head-discharge relationships of this new modified gate were proposed based on dimensional analysis and the incomplete self similarity concept. In these relationships, the flow rate is related to the upstream depth, the gate opening, and the cylinder diameter. The proposed equation is accurate and practical so that it removes the need to consider the discharge coefficient. Results showed that this equation can be fitted to laboratory data very well. The mean relative error for estimation of discharge in the free and submerged conditions was less than 2 and 5 percent, respectively. Therefore, these equations can be used as a design tool for slide gates with cylindrical edge.