Numerical investigation of vibration and noise radiation of a water supply pipeline

The vibration and noise radiation from underwater structures can be harmful for aquatic ecosystems, especially for endangered species which are sensitive to particle motion and sound pressure. In this study, a water supply pipeline was chosen to investigate the flow-induced vibration and underwater noise radiation. A finite element model was developed to predict the vibration of the pipeline-tunnel-soil coupling system using fluid-structure interaction analysis. Next, a three-demission boundary element acoustic model was developed to simulate underwater noise radiation and propagation. Parametric analysis was conducted to investigate the influence of scouring depth on vibration and acoustic radiation. The results showed the flowing fluid-induced vibration produced broad band noise radiation, with dominant frequency range from 3 to 25 Hz. The sound pressure radiated from the model with once-in-a-century scouring depth was about 3 dB larger than the model with normal depth due to thinner sediment. The sourcing depth has significant influence on the noise distribution and radiation directivity. The simulated sound pressure level and water particle motion can exceed the threshold of some underwater species in certain frequency range, especially for the once-in-a-century scouring depth. The proposed methodology can be used for acoustic radiation prediction in further study to reduce the influence on aquatic environment.