Study of Flow over Labyrinth Spillway

Abstract

Side weirs are commonly used as diversion structures in hydraulic and environmental engineering applications. For sites where an increase in width of side weir opening has a limit, and discharge capacity of side weir is required to increase without changing the height of weir crest, then labyrinth side weir is a better alternative. A Labyrinth side weir provides an effective way to increase weir crest length which increases discharging capacity of the side weir. Both triangular and rectangular parent channels were considered for the investigation. In both parent channels, only triangular Labyrinth side weir was considered for the study. The present investigation is composed of two cases: 1) Investigation for hydraulic behaviour of triangular Labyrinth side weir in the triangular channel. 2) Effect of the width of rectangular parent channel on Cd of triangular Labyrinth side weir. newlinePrevious studies on the side weir have focused on labyrinth side weir considering rectangular parent channel. In the present investigation numerical simulation has been carried out for triangular labyrinth side weir in triangular parent channel. The included angles of triangular labyrinth side weir were taken as 600,900 and 450. Dimensional analysis has been carried out to find non-dimensional parameters of Cd. An empirical equation for Cd is proposed considering non-dimensional parameters such as Froude number, L/l ratio, h/P ratio, included angle of labyrinth side weir and included angle of the triangular channel. The equation is formulated for the coefficient of discharge of triangular labyrinth side weir in the triangular channel. It was found that the equation formulated has a good agreement with experimental results within the error range of ± 5% to 6% newlineThe numerical investigation has been carried out to find the effect of width variation of rectangular parent channel on Cd. To get the effect of the L/B ratio on Cd, width of parent rectangular channel has been increased without change in non-dimensional parameters such as Froude num