In order to accurately grasp the vibration and sound characteristics of pipelines, a numerical simulation is carried out.

Based on the theory of acoustic-solid coupling, a numerical model of a pipeline is established. The dispersion curve of the vibration and acoustic modes of the pipeline is solved by parametric scanning. The dispersion characteristics of the elastic wall pipeline with air, water and crude oil, as well as the absolute pressure stress distribution in the pipeline, are analyzed, and the effects of wall thickness, elastic wall and hard sound field wall on the dispersion characteristics of the pipeline are studied.

The results show that wall thickness has little effect on the propagation mode of elastic waves in the pipeline, and the dispersion curve is shifted to high frequency with the increase in wall thickness, mainly influencing the cut-off frequency. Due to the effects of acoustic-solid coupling, the number of modes of the elastic pipeline increases, and the increased mode number is mainly the deformation mode of the pipeline wall. The absolute sound pressure distribution in the elastic wall is basically the same as that in the hard sound field wall. The dispersion characteristics of liquid or gas inside are different, while the dispersion characteristics of water or oil inside are similar, but the direct modes of the two are different.

The results of this study can provide a theoretical basis for the pipeline acoustic detection of ships.