A review of computational models for underwater acoustic radiation induced by structural vibration in the shallowmarine environment

Abstract

<p indent="0mm">The vibration and acoustic performance of underwater structures have always been a research hotspot in the field of ocean engineering. The acoustic stealth technology of submarines and the marine hydroacoustic detection technology are based on the accurate prediction and effective control of the underwater structural vibration and acoustic behavior in the marine environment. For vibration and acoustic analysis in the marine environment, most of the early studies regarded the marine environment as an infinite fluid region, or a semi-infinite fluid region with a free sea surface. These two marine models simplify the simulation process of underwater acoustic radiation and propagation by ignoring the impact of the seabed. Underwater acoustic radiation and propagation caused by structural vibrations in the shallow marine environment will be greatly affected by the reflection and refraction effects at the sea surface and seabed. Moreover, the sound velocity in the shallow marine environment usually shows different profiles due to the influences of the water pressure and temperature, which affects the vibration and acoustic behavior of underwater structures. To accurately characterize the coupling effect of underwater structures and shallow marine environments, many researchers have devoted their particular efforts to the analysis of vibration and acoustic radiation of underwater structures in the shallow marine environment, and have developed a variety of numerical computational models, such as the finite element method, finite element-boundary element method, finite element-wave superposition method, finite element-singular boundary method, finite element-parabolic equation method and finite element-normal mode method, and so on. This paper focuses on deterministic computational models for vibration and acoustic analysis of underwater structures in the mid-low frequency range, and discusses two analytical schemes: Wet modal analysis and dry modal analysis. The development and application status of the computational models for the vibration and acoustics of underwater structures in the shallow marine environment are reviewed from the aspects of underwater acoustic models and numerical algorithms. Among those computational models, the finite element method combined with absorbing boundary layers is a common and efficient computational model, which is suitable for the analysis of near-field acoustic radiation induced by structural vibrations in the shallow marine environment. By contrast, the boundary discretization schemes, such as the boundary element method, wave superposition method and singular boundary method, avoid the special truncated treatment of marine domains by using the Green’s function derived from the mirror virtual source method and the normal mode model. Therefore, the hybrid computational solvers, such as the finite element-boundary element method, finite element-wave superposition method and finite element-singular boundary method, can be applied to the analysis of vibration and acoustic behaviors of the near- and far-field vibration and acoustic analysis. On the other hand, based on the wet modal analysis, the finite element-wave superposition method, finite element-parabolic equation method and finite element-normal mode method have higher computational efficiency in far-field acoustic propagation problems induced by vibration of underwater structures. Finally, the future development and application prospect of computational models for vibration and acoustic analysis of underwater structures in the shallow marine environment are discussed. Most of the existing computational models are based on the shallow marine environment of the horizontal sea surface and seabed. In future development, it is necessary to broaden the application scope of computational models, improve the computational efficiency of numerical algorithms, introduce the efficient optimization algorithm to develop a high-performance computational model for the optimal design of vibration and noise reduction of underwater structures in the typical and complex shallow marine environment.