Calculation method of acoustic radiation for floating bodies in shallow sea considering complex ocean acoustic environments

For floating bodies in shallow sea, the prediction of acoustic radiation requires consideration of complex acoustic environments. Generally, the influence of the sea surface, seabed and sound speed profile cannot be neglected. In this paper, a relevant calculation method in shallow sea considering the sound speed profile is developed by introducing the Green's function corresponding to a complex ocean acoustic environment into the three-dimensional sono-elasticity theory for ships. The inviscid, irrotational and compressible fluid, which can be regarded as an acoustic medium, is considered. The fluid load is taken into account by hydrodynamic coefficients during the fluid-structure coupling vibration analysis. The structural vibration response is obtained by the modal superposition method. The simple-source method is employed to calculate the acoustic field. The mirror method and the normal mode method are applied in the calculation of near-field and far-field Green's functions respectively. A series of numerical examples are given and the results are compared with those of the full FEM approach to verify the accuracy and applicability of the presented method.