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[摘要]
为研究台阶式溢流坝不设反弧段连接时消力池底板压强特性,结合某水库实际工程,采用物理模型试验方法,对台阶式溢流坝消力池底板时均压强、脉动压强强度和峰值等压强特性进行了研究。结果表明,消力池底板时均压强均为正值;在滑行水流和过渡水流时,时均压强在水流冲击区出现一个较大值,最大为0.926 kPa,下游反弹区形成极小值;在跌落水流时,时均压强沿程变化较小,且随流量的增加而增大;脉动压强强度和峰值沿程变化规律基本一致,总体上随流量的增加而增大,最大值出现在水流冲击区,脉动压强最大为1.198 kPa,随后沿下游方向逐渐减小,并趋于稳定;台阶尺寸对消力池底板时均压强和脉动压强影响不大;消力池内脉动优势频率为0.01~4 HZ,属低频振动,不会危害泄水建筑物的安全。 关键词:消力池;台阶式溢流坝;时均压强;脉动压强;频率
[Key word]
[Abstract]
To study the pressure characteristics in the stilling basin of a stepped spillway without anti-arc, we chose a reservoir and used the physical model test method to study the pressure characteristics including time-average pressure, fluctuating pressure intensity, and peak pressure pulsation in the stilling basin of a stepped spillway. The results showed that all the time-average pressure was positive in the stilling basin. When the flow regime was skimming flow and transition flow, the time-average pressure became large in the flow impact area, reaching a maximum of 0.926 kPa; it reached the minimum in the downstream rebound zone. The time-average pressure varied slightly when the flow regime was nappe flow, and increased with the increase of flow. The variation patterns of the fluctuating pressure intensity and peak pressure were basically consistent. They both increased with the flow on the whole. The maximum value appeared in the flow impact zone. The maximum fluctuating pressure was 1.198 kPa. It then decreased gradually in the downstream direction until it became stable. The step size hardly affected the time-average pressure and fluctuating pressure on the floor of the stilling basin. The dominant frequencies of fluctuations in the stilling basin were 0.01 – 4 HZ, which belonged to the low-frequency vibration and will not endanger the safety of drainage buildings.
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