【摘要】 闸门是一种控制水位和流量的建筑物,其出流特性与出流计算是工程水力学中颇为关注的问题.对淹没出流条件下冲刷坑形成过程中,闸孔出流的泄流能力、冲刷坑内水流流态及机械能的变化尚未开展研究,通过数值模拟对此进行了探讨,得到如下成果:1)在闸孔出流过程中,伴随着河床底部边界的变形及水跃的调整,过闸流量有变化但变化很小;2)在闸孔出流过程中,冲刷坑内的回流形态不断调整,重汇点位置也从冲刷坑形成初期的最大冲深位置下游不断回缩,直至与最大冲深位置相当;3)在闸孔出流过程中,伴随着河床底部冲刷的发展,闸门下游急变流段水流运动的总机械能损失是朝着减小的方向调整的,且机械能损失系数随冲刷时间不断减小趋于某一定值.更多还原

【Abstract】 Sluice gate is a facility for controlling discharge and water level,whose discharging characteristics and calculation is often considered in engineering hydraulics.Although there are abundant existing research achievements,the discharge capacity of discharge under sluice gate,the flow pattern in the scour hole and the change of mechanical energy loss in the forming process of local scour hole under the submerged discharge conditions are still not investigated yet.The main conclusions are as follows in this paper:(1)In the discharging process,the river bed is scoured continuously,and the hydraulic jump is adjusting accordingly.Meanwhile,the flow discharge is varying but the variation is very tiny.(2)In the discharging process,the backflow pattern is adjusting continuously in the scour hole,and the reattachment point is also moving upstream from the initial location downstream of the maximum scour depth till it corresponds with the maximum scour depth position.(3)In the discharging process,with the development of the river bed scouring,the mechanical energy loss of the total flow behind sluice gate is adjusting toward the direction of decreasing;and the coefficient of mechanical energy loss is continuously decreasing and is trending to a stable value with the scouring of time.更多还原