Experimental Measurement of the Discharge Coefficient for the Inclined Sluice Gates

Sluice gates are hydraulic devices that regulate channel discharge or redirect water flow from primary to secondary channels. These gates may be positioned in many ways; Some gates are vertical, whereas others are tilted either in the direction of flow or against it, contingent upon their special design function. In this study, several models of sluice gates were considered in different positions in the direction of flow and against it. The sluice gate angles considered were 10°, 20°, 30°, 40°, and 45° in the direction of flow and against flow direction under free flow condition, with the reference position set at 90°, the study was examined how the inclination of the gate influence the amount of discharge coefficient and how the discharge coefficient was affected by the variation in upstream water depth and gate opening height, where the four gate opening heights were (1, 2, 3, and 4) cm. The aim of this research is to determine the discharge coefficient under inclined sluice gates in different positions; furthermore, a general equation of free flow under inclined sluice gates has been established. According to the findings, the discharge coefficient (Cd) increases as the inclination angle of the sluice gate in the direction of flow increases and decreases as the inclination angle of the sluice gate against the direction of flow increases. Also, increasing the gate opening (h) will reduce the discharge coefficient (Cd) to pass the same amount of water through the sluice gate. Finally, empirical equations were derived linking the discharge coefficient values passing under the vertical and incline sliding gates for various openings and conditions using the non-linear regression analysis in (SPSS) program. Additionally, the statistical indices (R2) and Nash–Sutcliffe efficiency (NSE) were used to test the reliability of these equations, and their results for the vertical sluice gate was 0.9868, 0.9766, the incline sluice gate with flow was 0.9897, 0.950 and the incline sluice gate against flow was 0.9793, 0.940 respectively. The analytical approach for estimating the coefficient of discharge under the vertical and inclined sluice gates showed a great fit with experimental findings.