1995 Fiscal Year Final Research Report Summary
Wave-free floating-body forms in shallow water and application to a very large floating structure
| Project/Area Number |
06651085
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
海洋工学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
KYOZUKA Yusaku Kyushu University, Interdiscip.Grad.School of Eng.Sci., Professor, 大学院・総合理工学研究科, 教授 (80177948)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Masahiko Kyushu University, Res.Inst.Appl.Mech., Asso.Professor, 応用力学研究所, 助教授 (40155859)
KOTERAYAMA Wataru Kyushu University, Res.Inst.Appl.Mech., Professor, 応用力学研究所, 教授 (80038562)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Wave-Free Body / Wave-Free Singularity / Wave Free / Wave Diffraction / Shallow Water / Boundary Element Method |
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| Research Abstract |
Some wave-free floating-body forms in heaving oscillation are obtained by using a wave-free singularity of source and vertical dipole combination to generate bulbous-shaped two-and three-dimentional bodies in shallow water. Body forms are obtained by the streamline tracing method at a planned wave frequency, where the body boundary condition of heaving oscillation is satisfied.
Effects of location of the wave-free singularity and water depth on the body-form are studied. Body forms become slender as water depth becomes shallow. Wave exciting forces of obtained bodies are calculated by the singularity distribution method in two-and three-dimentions to verify that they become wave-free at the planned wave-number.
Model experiments were conducted in 2D and 3D wave tanks. Wave exciting forces of obtained wave-free bodies were measured in regular waves. Wave-free frequency estimated by amplitude reaponse function of heaving excitation is almost same as the theory but a little bit higher, which may be attributed to nonlinear effects such as viscosity of water. Finally, some proposal are made to apply such a wave-free body to a very large floating structure (VLFS) of semi-submersible type.
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