| Project/Area Number |
63550376
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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 |
Hydraulic engineering
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| Research Institution | Ehime University |
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Principal Investigator |
NAKAMURA Takayuki Associate Professor, Department of Ocean Engineering, Faculty of Engineering, Ehime University, 工学部, 助教授 (60108404)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Offshore breakwater system / Effective spatial array / Wave transmission and reflection / Green's function method / Wave height attenuation / Wave direction control / Wave resonance / Resonator-type breakwater / 沖合消波堤 / 波高分布 / グリーン関数法 / 多列式堤体 / 共振装置型堤体構造物 |
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| Research Abstract |
(1)Study on numerical approaches on water wave problems around infinitely arrayed 3-D bodies. In order to clarify the spatial allocation of offshore breakwaters for effective attenuation of incoming waves to the shore, analytical procedures of wave interaction among infinitely arrayed offshore breakwaters were developed. Where the following three different approaches were derived, mainly depending upon the configuration of individual breakwater. a)Efficient and practical approach on water wave problems around a 3-D body with plane symmetries. b)Analysis on wave interactions among infinitely arrayed surface piercing structures. c)Analysis on wave interactions among infinitely arrayed 3-D bodies of arbitrary shape.
(2)Effective ways for wave attenuation and wave directional change by an array of offshore breakwaters. Changing both the spatial allocations of breakwaters and configurations of individual breakwater, characteristics of wave transmission and reflection as well as wave directio
… More
nal change by infinitely arrayed offshore breakwater system were examined from both the analytical and experimental points of view. Where the analytical procedures developed before were adopted. The results obtained are summarized in the followings. a)Two dimensional wave diffraction effects are important when a wave length of incoming wave is smaller than the center-to-center distance of aligned breakwaters, because of emerging transverse waves around the breakwater system. In this case, directional characteristics of transmitted and reflected waves should be taken into consideration for assessing the wave attenuation effect. b)Attenuation effects by an array of offshore breakwaters are not significantly depending upon the spatial allocation ways, e.g. linear array and staggered array etc. but heavily depending upon opening ratio of arrayed breakwaters and the ratio of a wave length to a center-to-center distance of neighboring breakwaters. c)Effective wave attenuation may be possible by the use of an array of resonator-type breakwaters. Less
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