【摘要】 采用高速摄像技术对陡槽内自掺气水流进行了观测,拍摄到了掺气起始区气泡在水流内部形成的完整过程,对气泡形成的过程进行了概化分析。水面附近涡体运动产生的脉动压强和水面相互作用,导致水面发生上凸下凹的变形。当这种变形达到一定程度后,受顺水流向或横向脉动压力、横向切应力的作用,深入水体凹坑的边壁在某一部位闭合,下部包裹空气形成气泡而发生自掺气。随着紊动强度进一步增大,水面变形加剧,表现为高高跃出水面的柱状突起和水滴,这些水柱的倾倒、聚并也会造成空气进入水中形成气泡。明渠水流自掺气是水体内部紊动与水面相互作用的结果。更多还原

【Abstract】 The high speed video camera was used to visualize the self-aeration process taken place at the high speed flowing water surface.The pictures show how air bubbles are formed in the developing zone of self-aerated water flow.The interaction of pressure fluctuation caused by eddies and free water surface makes the strong deformation of surface.Once the deformation reaches a specific limit,the air will be captured into the water flow and forms the air bubble,which implies the beginning of self-aeration.When the turbulence of flow develops sufficient energetically,the water surface breaks and creates water drops,bubbles and fully mixed two-phase flows.This means that the turbulence at free surface results in the self-aeration of open channel flows.更多还原