Hydraulic Perspective for Flow over Parabolic Weir and under Parabolic Gate

Abstract

The weir-gate structure is a very important discharge structure. Thus, understanding the hydraulic features of this structure is necessary. The water flow over the weir and under the gate was investigated experimentally. Both the weir and gate have a parabolic shape; therefore, this paper aims to understand the appropriateness of using a non-regular shape in the hydraulic features of the discharge structure. The following variables and parameters are adopted in this study: actual discharge, water depth above the weir crest, vertical distance between the weir and gate, cross-sectional area of flow that crosses the weir and gate, downstream water depth, discharge coefficient, Froude number, and Reynolds number. It is found that all these hydraulic variables and parameters depend mainly on the water flow velocity, water flow depth, and flow area that cross the weir and gate, respectively. As well, the variation in the results trend will be attributed to overlapping between weir flow velocity and gate flow velocity. The use of a weir and gate with a parabolic shape produces a slight alteration in some hydraulic features, and this can be considered one benefit of using a non-regular shape for the discharge structure. The conflict between water flow velocity and water flow depth will be reflected directly in the Froude number and Reynolds number.