Summary: | 碩士 === 國立臺灣海洋大學 === 輪機工程學系 === 107 === In this thesis, we use the finite element method to solve the underwater acoustic radiation of underwater vehicles with reinforced ribs. The designs of underwater vehicles have to take into account the limit of space and weight, while the reinforced ribs can achieve the purpose of increasing the stiffness of the structure with minimal mass. However, after the structure is excited by an external force, it causes the coupling characteristics and acoustic radiation. Therefore, it is necessary for exploring the underwater acoustic radiation to investigate the fluid-solid interaction. We use the finite element method to solve the problem of fluid-solid interaction and the underwater acoustic radiation. Because of the different solving matrix, the computation efficiency of the finite element method is better than the boundary element method. When the structure is installed with reinforced ribs, the coupling faces of the structure and the acoustic cannot be completely matched. It causes that the boundary is discontinuous and errors in the calculation results. In this thesis, we add a small distance of the structure to create the acoustic mesh. It makes the coupling faces of the structural mesh and the acoustic mesh completely fit, and keep the continuity of boundary. Finally, we compare the theoretical and numerical solutions to verify the feasibility and accuracy of this method. The numerical results and the solution flow have the value in engineering application.
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