【摘要】 当yc/h<3时,3种坡度(40°、50°和60°)的台阶式溢流坝试验结果证明,在初始台阶上,作用在水平面上的时均压强均为正值,其最大压强随流量增大,由台阶中部逐渐移向台阶外边缘;跌落水流时台阶竖直面上部范围出现的负压,在进入过渡水流以后全部变为正值。其他各台阶水平面上,除挑射水流越过的数个台阶外,在各级流量下时均压强为正值,其最大值均在台阶外边缘;台阶竖直面上部的时均压强为负,下部的时均压强为正,随流量增加负压绝对值增大,范围缩小。其中跌落水流时负压占台阶高度的75%,进入过渡水流后负压约占台阶高度的60%。更多还原

【Abstract】 Experimental results on the stepped overflow dam(respectively with a slope of 40°,50° and 60° when(y_c/h)<3) show that on the first step,the mean pressure on the horizontal plane is positive,and the maximum value moves from the middle to the edge with the increase of discharge;the negative mean pressure appears on the upper part of the vertical plane in nappe flow while mean pressure becomes positive in transition flow.Except the few steps jumped over by jump flow,the mean pressure on the horizontal plane of all the other steps is positive and the maximum value is on the edge of steps.On the vertical plane of a step,the mean pressure appears negative on the upper part while it becomes positive on the lower part.With the increase of discharge,the absolute value of negative mean pressure increases while its regime dwindles.The negative pressure reaches 75% step height in nappe flow and 60% step height in transition flow.更多还原