Dept. of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada E-mail:
Water Sci Technol. 2021 Jan;83(1):173-183. doi: 10.2166/wst.2020.560.
Storm geysers have received significant attention lately due to its more frequent occurrences and the induced severe local flooding and infrastructure damages. Previous studies suggested that the air pocket pressure oscillated during geyser events especially in rapid filling process, but only the peak values were studied and the oscillation period was not discussed in detail. In this paper, a theoretical model was developed focusing on the period of the pressure oscillation induced by the expansion/compression of the air pocket below a water column in a vertical riser with film flow. It was found that the oscillation period was a function of the initial air pocket volume, initial air pocket pressure head, the riser diameter, and the initial water column length. The oscillation period increased with the air pocket pressure head and the air pocket volume, but decreased with the riser diameter and the polytropic coefficient. The oscillation period increased then decreased with an increasing water column length. Further, when considering the film flow along the riser, the oscillation period decreased slightly from the analytical solution. It was also found that the inflow rate change did not significantly influence the oscillation period.
由于风暴喷泉更加频繁地发生，并导致严重的局部洪水和基础设施损坏，因此最近受到了广泛关注。先前的研究表明，在喷泉事件期间，气穴压力会发生波动，特别是在快速填充过程中，但仅研究了峰值，而没有详细讨论波动周期。本文开发了一个理论模型，重点研究了在垂直立管中，水柱下的气穴在膨胀/压缩过程中引起的压力波动周期。结果表明，该波动周期是初始气穴体积、初始气穴压力水头、立管直径和初始水柱长度的函数。波动周期随气穴压力水头和气穴体积的增加而增加，但随立管直径和多方指数的增加而减小。随着水柱长度的增加，波动周期先增加后减小。此外，当考虑沿立管的膜流时，该波动周期相对于解析解略有减小。研究还发现，流入速率的变化对波动周期的影响不大。
