Numerical investigation on dynamic characteristics of oil-water annular flow-induced vibration in curved pipes

To improve the stability of water-lubricated transportation and reliability of pipes in service, the fluid–structure interaction numerical model has been established to investigate the dynamic characteristics of oil-water annular flow-induced vibration in curved pipes and the effect of main parameters in this study. The results illustrate that a single vibration mode of curved pipes is excited by oil-water annular flow, and there exists no multi-modality due to the limited pulsation of pressure and interface of two-phase flow. The change of velocities and oil-water ratios leads to change of flow pattern, making the dynamic response severer. When the oil-water ratio is larger than 2.035, its effect is greater than velocity. The physical properties of oil have a significant effect on the dynamic response. The root-mean-square dimensionless displacement A Y,RMS /D and maximum dimensionless displacement A Y,MAX /D of fuel oil-water annular flow-induced vibration decrease to 75.6% and 76.5% respectively, which means that the increase of dynamic viscosity reduces the fluid force and suppresses the vibration. A Y,RMS /D and A Y,MAX /D increases by 1.62 times when the bending angle θ increases from 30° to 90°, indicating that the increase of bending angles also leads to the severer dynamic response.