【摘要】 有压洞出口后的突扩突跌掺气减蚀设施在水利工程中经常使用。由于水流受边界条件和掺气的影响,其流态和脉动压力往往与普通水槽的情况有很大的不同。通过水工模型试验,对突扩突跌掺气设施后泄槽底板上的脉动压力进行研究,揭示了掺气设施后泄槽底板上不同流动区域的脉动压力特性。从脉动压力的时域过程、均方根值、偏态系数、峰态系数和主频率等多方面得出冲击区、反射区和稳定区脉动压力的特性是不相同的结论。同一流量时,沿流程底板的时均压力都大于脉动压力的均方根值,在冲击区、反射区和稳定区,脉动压力的均方根值分别是同位置时均压力值的约0.5倍、0.6倍和0.7倍。研究成果可为更好地利用突扩突跌掺气设施提供有益的理论和试验依据。更多还原

【Abstract】 The aeration facility with sudden lateral enlargement and vertical drop is commonly adopted in water conservancy project.Due to the water flow therein is under influences from the relevant boundary conditions and aeration,its flow regime and fluctuation pressure are often more different from those in the conventional water flume.Through hydraulic model experiment,the fluctuation pressure on the chute bottom slab behind the aeration facility with sudden lateral enlargement and vertical drop is studied herein,and then the characteristics of the fluctuation pressures on the chute bottom slab behind the aeration facility within various flow regions are exposed.The conclusion of that the characteristics of the fluctuation pressures within the impacting region,reflecting region and stable region are different is obtained from the aspects of the time-domain process,root-mean-square value,coefficient of skewness,kurtosis coefficient,main frequency,etc.of the fluctuation pressure.During the same flow rate,all the time-averaged pressures on the bottom slab along the flow path are larger than the root-mean-square values of the fluctuation pressures,while the root-mean-square values of the fluctuation pressures within the impacting region,reflecting region and stable region are 0.5 times,0.6 times and 0.7 times of the time-averaged pressures at the same positions respectively.The study result can provide a theoretical and experimental basis for better application of the aeration facility with sudden lateral enlargement and vertical drop.更多还原