Study on the effect of different bed sills on flow structure and scouring at the bed of channel

Stabilizing the banks and bed of the river is one of the most important problems in river engineering. This importance arises from the scouring of the banks and bed of a river impacting on hydraulic structures and the aquatic environment. Using a bed sill is one way of mitigating bed and bank scouring. Both experimental and numerical techniques were employed to analyse concave, convex and sine bed sills. It was found that a concave bed sill developed vortices at the banks and transferred sediments to the middle of the channel. This caused stability of the channel's centre when compared to the convex bed sill. Such stability leads to the stabilization of banks by creating the maximum depth of scour at the centre of the channel. Since both concave and convex bed sills stabilize only bed or banks, other types of bed sills such as sine shape was also tested in stabilization of both bed and banks. The distance of vortices location from the bank could affect the stability of bed and banks of the channel. The experimental observation confirmed that the maximum and minimum of scouring depth was related to the concave and convex bed sills, respectively.