Transient Vibration Characteristics of Complex Liquid-Filled Pipelines Considering Fluid–Structure Interaction: Model and Solution

Current research on the transient vibration characteristics of liquid-filled pipelines primarily focuses on simple straight or elbow pipe systems, with limited attention to complex pipeline configurations that incorporate essential components such as supports, flexible hoses, and fluid pulsation attenuators. To address this gap, this study first adopts a generalized fluid–structure interaction 14-equation model that is uniformly applicable to both steel pipes and flexible hoses, serving as the model foundation for characterizing complex pipeline dynamics. The model is then solved by the operator splitting technique combined with the second-order Godunov method, in which the interfacial fluxes of each control volume are computed through an exact Riemann solver. The excitation sources and supports are incorporated into the solution process via boundary matrices and intermediate node matrices. In contrast to previous research that is limited to free-standing straight or elbow pipes, the proposed method can systematically account for complex boundary conditions, multiple supports, and pipeline attachments, effectively avoiding the numerical damping that plagues the traditional method. The accuracy of the proposed model and solution approach is validated against two experimental cases drawn from published literature, demonstrating its capability to accurately predict transient vibration responses in liquid-filled pipelines. Furthermore, the developed method is applied to a representative shipboard hydraulic pipeline system to investigate the influence of key vibration reduction elements on the system’s transient responses under water hammer excitation. The results reveal that the support stiffness rather than the support damping dominates the structural transient response, while the hose may induce resonance under broadband water hammer excitation. These findings provide valuable insights for the low-noise design and optimization of practical liquid-filled pipeline systems.