Evaluation and modeling scouring and sedimentation around downstream of large dams

Flip buckets are often used at the end of chute spillways to dissipate energy and direct flow to submergence plunge pool and especially in large dams. Flip buckets with central deviation also are a specific and new design of these buckets that have a transverse slope and are mixed in plan with a curvature. In this paper, the experimental and numerical simulation study of sediment scouring in such flip bucket has been targeted. Extensive experimental data are obtained from physical model studies conducted at Water Research Institute, Iran. The flow field with various flood discharges in a range of Froude numbers ( Fr = V / gh : 3.5–7.5) in Flow3D model was compared to experimental results obtained from a similar model. Analyzing the simulated models in the Flow3D model and comparing the results with the experimental model, the hydraulic parameters of the pressure, velocity and depth of flow are determined. Considering the accuracy of the numerical model in simulating bed scouring, this model can be used for similar cases in large dams. The results of the simulation model compare well with the experimental results in parameters of the maximum scour depth, profile scouring and the ridge height which accumulates around downstream of the scour hole. This investigation improves the understanding of bed topography effects of downstream dams in high-velocity jet impact based on experimental observations and simulation analysis.