分段低压输水系统中堰井段水面波动数值模拟

Numerical Simulation of Water Surface Fluctuation in Weir Well Segment of Stepped Low-pressure Water Supply System

为研究输水系统中堰井段水面的波动现象,采用Realizableκ-ε紊流模型耦合VOF法对分段低压输水系统进行二维数值模拟,分析了堰后水深对水面波动规律的影响,探讨了在外加扰动作用下水面波动的规律。结果表明,堰后存在高、低两个水位区间,堰后水位处于这两个区间时,水面将会以某一主要频率稳定持续地波动;当堰后水位处于这两个区间之外时,水面波动变得无规律或只有微弱的波动。外加扰动对水面波动会造成一定影响,当外加扰动频率与水面波动固有频率一致时,即使外加扰动强度很小也会引起水力共振,水面波动幅度大大增加;外加扰动频率与固有频率相差较大时,水面波幅在某些特定时刻达到最大,然后减小到最小值,再增大到最大值,波动幅值的变化呈周期性,并推导出了相应的周期公式,为相关研究提供了参考。

The Realizableκ-εmodel coupled with volume of Fluid（VOF）method was applied to numerically simulate the phenomena of water surface fluctuation in weir well segment of the long-distance stepped low-pressure water supply system.The impact of water depth after the weir on the law of water surface fluctuation was analyzed and the law of water surface fluctuation under external disturbance was also studied.The results show that there exists a low water level interval and a high water level interval,water surface will fluctuate steadily and continuously at a certain frequency when the water depth after the weir is in the two intervals,while the water surface fluctuation will become disordered or only slight fluctuation when it is not in the two intervals.It can cause some influence on the water surface fluctuation when adds external disturbance even a low strength external disturbance can cause the hydraulic resonance,then the fluctuation amplitude of the water surface will be greatly increased when the external disturbance frequency is consistent with the natural frequency of water surface.When disturbance frequency and natural frequency has larger difference,the fluctuation amplitude will reach the maximum value in a certain time,and then decreased to the minimum value,and then increased to the maximum value,the variation of the amplitude is periodic.The corresponding periodic formulas are derived,which provides reference for correlative research.