底孔形状对坝前冲刷漏斗的影响试验研究OA

Reservoir sedimentation threatens the water intake safety of hydropower stations.A scour funnel formed upstream of the dam by sediment flushing through a bottom orifice is one of the most commonly used measures to ensure the intake of clear water in hyper-concentrated river reservoirs.Previous studies mainly focus on the effects of hydrodynamic and sediment factors on the size of scour funnel under the equilibrium state of erosion and deposition,while the influence of bottom orifice shape remains relatively limited.Under identical flow area and waterhead,a series of flume experiments was conducted using circular and square orifices as representatives to investigate the effects of orifice shape on the formation process and geometry size of the scour funnel.The differences between the two when a structure(represented by a thin rectangular cuboid)is arranged upstream of the bottom orifice are also explored.Results show that under the same experimental conditions,regardless of the presence of the structure,the relative deviation of the maximum scour depth of the equilibrium scour funnel formed by circular and square orifices does not exceed 9.5％,while the relative deviations of transverse and longitudinal slopes are less than 3.8％and 2.6％respectively.