Investigation of Air Pocket Behavior in Pipelines Using Rigid Column Model and Contributions of Time Integration Schemes

This paper studies the air pressurization problem caused by a partially pressurized transient flow in reservoir-pipe system. The purpose of this study is to analyze performance rigid column model predicting attenuation pressure distribution. In regard, an analytic formula for amplitude and frequency will be derived, which influential parameters, particularly, driving water lengths, on damping can seen. direct effect inverse product lengths numerically examined. addition, these numerical observations examined solving different test cases comparing available experimental data show that able predict damping. However, due simplified assumptions associated with model, energy dissipation, as well damping, underestimated. using backward Euler implicit time integration scheme, instead classical fourth order explicit Runge–Kutta proposed so dissipation scheme represents physical dissipation. derived calculate appropriate step size, heat transfer compensated.