Studying sub-atmospheric pressure patterns in emptying pipeline systems is crucial because these processes could cause collapses depending on the installation conditions (the underground pipe covering height, type, fill, and pipeline stiffness class). Pipeline studies have focused more on filling than on emptying processes. This study presents an analysis of the following variables: air pocket pressure, water velocity, and water column length during the emptying of an irregular pipeline without an air valve by two-dimensional computational fluid dynamics (2D CFD) model simulation using the software OpenFOAM. The mathematical model predicts the experimental values of the study variables. Water velocity vectors are also analysed within the experimental facility, assessing the sensitivity of the drain valve to different openings and changes in water column length during the hydraulic phenomenon.

中文翻译：

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使用 2D CFD 模型分析不带空气阀的不规则管道排空期间的次大气压

研究排空管道系统中的次大气压模式至关重要，因为这些过程可能会导致坍塌，具体取决于安装条件（地下管道覆盖高度、类型、填充和管道刚度等级）。管道研究更多地关注填充而不是排空过程。本研究通过使用 OpenFOAM 软件的二维计算流体动力学 (2D CFD) 模型模拟，对以下变量进行了分析：在没有气阀的不规则管道排空期间，气穴压力、水速和水柱长度。数学模型预测研究变量的实验值。水流速度矢量也在实验设施内进行分析，