变缝宽异型构造底板脉动压力特性试验

Experimental study on characteristics of fluctuating pressure in special-lshaped plunge pool slabs with changing gap width

在水利工程中,水垫塘是大坝的重要安全防护设施之一,在高速水流冲击下,水垫塘的安全与稳定关系到大坝能否正常运行。以某消力塘水工模型试验为背景,结合模型试验结果,对比分析了不同缝隙宽度对底板下表面脉动压力特性的影响。研究表明：在水跃稳定区,带键槽底板下表面的脉动压强系数会随着键槽间的缝隙宽度的增大而增大,带键槽底板概率密度分布图的正态性较好;当键槽缝隙宽度增大时,带键槽底板可能产生的最大脉动上举力有所减小;对于相同测点,键槽缝隙宽度越大,下表面缝隙涡旋的平均尺度和脉动压力空间积分尺度都越大;随着键槽缝隙宽度变小,带键槽底板下表面的脉动能量更加集中于低频。

In hydraulic engineering,the plunge pool is the key to the safety of protecting structure.It affects whether the dam can operate safely or not under impact of high-speed water flow.Based on a plunge pool hydraulic model test and its results,this paper discussed the characteristics of fluctuating pressure acting on the under-surface of the slab with different gap widths.The analysis results showed that in the stable hydraulic jump area,the fluctuating pressure intensity coefficient of slab with keyway increased with the increase of the gap width between slot plates.The probability density distribution was in accordance with the normal distribution.When the gap width increased,the maximum fluctuating uplift force decreased.At the same point,the greater the gap width was,the greater the average eddy scale and spatial integral scale were.With the decrease of the gap width,the pressure fluctuation energy of slab was concentrated more on low frequency section.