Flow characteristics of rectangular sharp-crested side weirs in the presence of guide vanes

Abstract A side weir is a type of overflow structure that is installed in the side of a channel to evacuate the excessive flow laterally. One of the simple ways to improve the hydraulic performance of this structure is the application of guide vanes. In this study, characteristics of flow over rectangular sharp-crested side weirs in the presence of guide vanes were experimentally investigated. In addition, the behavior of the flow in the absence of vane plates was considered for comparison. Analyzing the measured 3D velocity distribution data indicated that the presence of guide vanes significantly decreased the longitudinal velocity and increased the magnitude of downward velocity over the crest. Furthermore, the presence of guide vanes increased the lateral velocity, thereby resulting in more discharge over the side structure. It also reduced the angle of the spilling jet with the normal to the plane of weir and caused the side weir to work more similarly to a frontal weir.