| Project/Area Number |
08455228
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NADAOKA Kazuo Tokyo Institute University Graduate School of Information Science & Engineering Professor, 大学院・情報理工学研究科, 教授 (70164481)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAISHI Tetsuya Port and Harbor Research Institute Ministry of Transport Hydraulic Engineering D, 水工部, 主任研究官
HINATA Hirofumi Tokyo Institute of Technology Department of Civil Engineering Research Associate, 工学部, 助手 (70272680)
NIHEI Yasuo Tokyo Institute of Technology Graduate School of Information Science & Engineeri, 大学院・情報理工学研究科, 助手 (60262268)
YAGI Hiroshi Tokyo Institute of Technology Department of Civil Engineering Associate Professo, 工学部, 助教授 (80201820)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥4,200,000 (Direct Cost: ¥4,200,000)
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| Keywords | wave equation / wave breaking / pressure gradient / breaking waves / turbulence model / phase-averaged model / long wave evolution / wave overtopping / 渦度 / 砕波減衰 / スペクトルモデル |
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| Research Abstract |
Toward the establishment of a general theory on water waves, numerical analysis and laboratory experiments on wave breaking were executed first in this study. Their results revealed that when a wave breaks the vertical pressure gradient becomes zero near the wave crest, suggesting that the vertical pressure gradient may be used as a useful breaking criterion. Incorporating this criterion into the wave model by Nadaoka et al. (1994-97), which can describe wave evolution at arbitrary depths under nonlinear and dispersive effects, a numerical simulation was performed for wave train traveling over a slope. The numerical results on the breaker depth show good agreements with those by Goda's empirical criterion. A breaking wave model was also developed in which a depth-integrated formulation is employed and the turbulence energy source due to the large-eddy production at the breaking wave crest is formulated. This model was demonstrated to give satisfactory results even for irregular waves breaking over slopes with various profiles. As another main subject of the study, phase-averaged models both for the Boussinesq equations and Nadaoka et al's equations were developed. These phase-averaged type models may serve CPU time quite efficiently and simulate nonlinear evolution of carrier and associated long waves. In relation to this work, a field observation was performed at Kajima port facing the Pacific Ocean to reveal the characteristics of long waves associated with group waves. Further the wave model by Nadaoka et al.was extended to handle waves generated by impinging of water mass overtopping a breakwater.
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