| The study of fluid-structure coupling such as the stability of the damaged ships,perforated breakwaters,and perforated fish boats can be attributed to the hydrodynamic characteristics of perforated floating thin-walled cylindrical structures.The hydrodynamic theory of perforated structure is not only a major and difficult problem to be solved in ocean engineering,but also has important engineering application prospects and should be investigated as a breakthrough by a ne w theory.In this paper,based on wave radiation and diffraction theory,boundary element method is chosen to establish the boundary integral equation for the interior and exterior domains of perforated structures.Transmission coefficient,reflection coefficient,added mass and damping,wave force and motion response of the perforated structure are calculated with high precision.The direct method is used to solve the hyper singular integral equation,and velocity of fluid particle around perforated floating cylindrical structure that with non-dimensional thickness of only 0.005 is obtained at first time.It founds that the current algorithm of boundary element method is very accurate and can be applied to the motion response problem of thin-walled structures with arbitrary geometry;And perforated structure can eliminate wave and reduce its amplitude and wave exciting force;The transmission and reflection coefficient of perforated structure are similar with those of the floating body,and the added mass,damping force and wave exciting force are similar with those of the submerged body;In some wave frequencies,perforated structure will resonate especially in the case of heave direction because of the interaction of the water of interior and exterior domains;velocity of fluid particle will become slow when the water intake increase.The abo ve findings can be applied to the analysis and design of perforated breakwaters or perforated fish boats,and also can provide theoretical guidance of the problem of damaged ships. |
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