Experimental study on hydro-suction removal of cohesionless bed material

The current study deals with experiments on hydro-suction removal of cohesionless bed material from reservoirs. The primary focus lies in scrutinizing the scour profile and the volume of bed material removed through hydro-suction. A comprehensive record of 252 datasets was collected from experiments done on various combinations of governing parameters. The resultant equilibrium scour profile exhibited a symmetrical configuration resembling a semi-ellipsoidal shape. Notably, for the densimetric Forude number equal to or less than 5.8, a small central hump within the scour hole was seen. The investigation found that the optimal sediment removal efficiency was obtained when the C/D ratio was zero (where C is the suction inlet height and D is the suction pipe diameter) and with the highest densimetric Froude number. The sediment to water volume removal was highest in the initial few seconds, and reduced swiftly, followed by a subsequent smaller peak and gradually decreased to zero at equilibrium. Empirical equations for computing maximum scour depth, scour radius, and scour profile at equilibrium also were developed, which predict values within a commendable ±10% error range.