| Project/Area Number |
62460161
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hydraulic engineering
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| Research Institution | The University of Tokushima |
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Principal Investigator |
MITSUI Hiroshi The University of Tokushima, Faculty of Engineering, Professor, 工学部, 教授 (30035589)
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| Co-Investigator(Kenkyū-buntansha) |
HOSOI Yosihiko ditto, Assistant Professor, 工業短期大学部, 助教授 (50127859)
MURAKAMI Hitoshi The University of Tokushima, Technical College, Professor, 工業短期大学部, 教授 (50027257)
NAKANO Susumu ditto, Lecturer, 工学部, 講師 (50198157)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1989: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1988: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1987: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Wave energy / Wave concentrator / Permeable breakwater / Submerged breakwater / Wave control / Wave overtopping / Water exchange / Aeration / 潜堤 / 波浪制御 / 越波促進 / 海水交流 / 波の反射 / 波の回折・散乱 / 波のエネルギー利用 / 透過防波堤 / 拡散係数 / 分数係数 / 拡散 |
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| Research Abstract |
Water Exchange by Reflection Walls as a Wave Concentrator
First, the effective height of submerged breakwaters was found out by model tests, that caused much wave overtopping and had small wave transmission coefficients. Next, wave concentration characteristics of V-arranged reflection walls were analyzed with the wave diffraction-scattering theory, and were compared with results of model tests. After all, it was found that the reflection wall had the most effective length for each open angle. Some basic models which were designed based on the above results and wave resonanec theory were tested in the wave tank, and quantities of wave overtopping were found to be enhanced at the submerged dike in the inlet channel connected to the wave concentrator. Furthermore, characteristics of wave concentration were studied on reflection walls of parabolic horn type and exponential horn type (this type has the cut-off frequency). It was concluded that the parabolic type walls of which forcus existe
… More
d in the inlet channel had the highest efficiency to collect wave energy, V type and the parabolic type of which forcus located at the inlet mouth had moderate one, and the exponential type had the lowest one due to the existence of much reflected waves.
Water Purification and Water Wave Control by Breakwaters
First, the characteristics of flow and diffusion due to the wave action against a breakwater were examined theoretically and experimentally. Second, the dispersion characteristics of the permeable breakwater were also studied which was installed in the uniform tidal flow. In the results, the effective gap geometry of the cross section was suggested for the split-type breakwater. The values of diffusion and dispersion coefficients in a harbor could be estimated near the breakwater which was exposed to the wave and the tidal flow. And after reaeration coefficients were estimated, Ii was found that the permeable breakwaters were effective to purify the water in the harbor. Furthermore, the effective breakwaters were proposed to control waves and to exchange water, which consisted of a submerged breakwater and a thin slit-type permeable breakwater. Less
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