Investigation of Free Flow Under the Sluice Gate with the Sill Using Flow-3D Model

Abstract

Sluice gates are widely used in irrigation networks, in order to control the water level and regulate the flow that enters the intakes. Creating a sill under the sluice gate reduces the height of the gate and the construction costs of the irrigation network and also affects the discharge coefficient. The main aim of this study is evaluation of the effect of the shape, height and location of the sill on the sluice gate’s discharge coefficient. In order to evaluate the effect of the shape and height of the sill on the hydraulic flow, Flow-3D model was employed and two different sill shapes (rectangular and semicircular) with different heights were used under the sluice gate. The results indicate that creating a sill under the sluice gate increases the discharge coefficient and the shape and height of the sill are the most important factors in its increase. When the ratio of the rectangular and semicircular sills’ height to the gate opening is 2 and 0.5, respectively, the discharge coefficient is maximum value and 8.3% and 23% more than the case without sill, respectively. In order to correct the discharge coefficient of sluice gate with sill, equations for rectangular and semicircular sills have been presented.