The influence of boundary conditions on simulation of pressure wave reflection in a pipe

Abstract

Previous studies have demonstrated that the flow characteristics of pressure waves in hydraulic experiments show two types of reflected waves: those with the same type pressure vibration trend and those with the opposite vibration trend, with the pressure amplitude equal to that of the original wave. Reflection characteristics in a simulation must be consistent with those found experimentally. To determine reasonable boundary conditions (BCs), the focus of this work was the simulation of pressure wave reflection under five combinations of BCs using computational fluid dynamics. Three three-dimensional simulation models were developed based on the k–ε turbulence model. Reflection characteristics were obtained under the different BCs. The results showed that the pressure boundary in the pipe simulated the reflected waves correctly. The reservoir was found to be more accurate than the pressure boundary, which reflected the slight fluctuation in the reflected wave. Both the wall boundary and the velocity boundary could be used to simulate valve operation. However, if intercepting part of the pipeline, the reflected wave showed phase advance and pressure amplitude attenuation compared with that at the same position in the original pipeline. This study is helpful for setting reasonable BCs in pressure wave simulations.