Effect of the length of the weir wall sections on hydraulic characteristics of labyrinth weir

Abstract

Abstract A labyrinth spillway is a weir to increase the length of the weir wall within a fixed width, by the zig-zag plan shape. The weir wall of the labyrinth spillway consists of upstream, downstream, and sidewall. To increase the performance, it is good to modifications of the length of the weir wall of the spillway. In this regard, several studies have been published, however, the effect of changing the length of the weir wall section has not been addressed. To fill this gap, this study aims to compare the hydraulic characteristics of flow over 4 physical models of labyrinth spillway by variation of the length of the weir wall section (e.g. A = 0, 150, 250, and 300 mm downstream wall) with the same total length of the spillway i.e. 870 mm length. By extending the length of the upstream, the downstream will extend too, and the sidewall will shorten. The results of this study indicated that increasing the length of the upstream and downstream walls leads to a reduction in the discharge coefficient (Cd ). For A = 0 mm, Cd max = 0.87; A = 150 mm, Cd max = 0.77; A = 250 mm, Cd max = 0.64; A = 300 mm, Cd max = 0.45. Thus, it can be concluded that a shorter length of upstream and downstream walls was more efficient hydraulically compared to the others.