台阶式溢流坝消力池压强特性试验研究

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0.926kPa,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1.198kPa,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。研究成果可为台阶式溢流坝消力池的优化设计提供参考。

Experimental study on pressure characteristics in stilling basin of stepped spillway

To study the pressure characteristics in the stilling basin of a stepped spillway w ithout anti-arc, we chose a reservoir and used the physical model test method to study the pressure characterist ics including time-average pressure, fluctuat ing pres-sure intensity, and peak pressure pulsation in the st illing basin of a stepped spillway. The results showed that all the time-aver-age pressure was positive in the stilling basin. When The flow regime was skimming flow and t ransition flow , the time-average pressure became large in the flow im pact area, reaching a maximum of 0. 926 kPa; it reached the minimum in the dow nstream re-bound zone. The time-average pressure varied slightly when the flow regime was nappe flow, and increased w ith the increase of flow . The variation patterns of the f luct uating pressure intensity and peak pressure were basically consistent. They both in-creased with The flow on the w hole. The maximum value appeared in the flow impact zone. The maximum fluctuating pressure was 1. 198 kPa. It then decreased gradually in the dow nst ream direction until it became stable. The step size hardly affected the time-average pressure and fluctuating pressure on the floor of the st illing basin. The dominant f requencies of fluctuations in the st illing basin were 0. 01~ 4 H z, w hich belonged to the low-frequency vibration and w ill not endanger the safet y of drainage buildings.