Study of integrated calculation method of fluid-structure coupling vibrations, acoustic radiation, and propagation for axisymmetric structures in ocean acoustic environment

Abstract

Based on a combination of the finite element method and wave superposition method (FEM-WSM), an integrated calculation method of fluid-structure coupling vibrations, acoustic radiation, and propagation for axisymmetric structures in ocean acoustic environments is proposed. The FEM was applied to study the dry mode of axisymmetric structures in a vacuum, and WSM was used to consider the fluid-structure interaction effects and calculate the acoustic radiation field in ocean acoustic environments. The method proposed combines the advantages of FEM and WSM. This method is suited for complex or large axisymmetric structures. Furthermore, it is more efficient than FEM, and the calculation range of the water is not limited. To simplify the calculation, the Green's functions corresponding to the propagation of specific ocean environments were calculated differently in the near and far fields. Using spherical and elliptical axisymmetric shells as examples, the results from the method proposed and COMSOL were compared to verify the correctness of the proposed model. In the calculation of the acoustic radiation field, the numerical errors from matrices, including partial derivatives of the Green's function with huge condition numbers, required the use Tikhonov regularization, and the efficiency was not influenced.