2007 Fiscal Year Final Research Report Summary
Transformation of Wave Groups and Associated Long-Period Waves during High Waves
| Project/Area Number |
17360233
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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 | Nagoya Institute of Technology |
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Principal Investigator |
KIOKA Wataru Nagoya Institute of Technology, Nagoya Institute of Technology, Dept, of Civil Engineering, Professor (10135402)
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| Co-Investigator(Kenkyū-buntansha) |
KITANO Toshikazu Nagoya Institute of Tachnology, Dept of Civil Engineering, Associate Professor (00284307)
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| Project Period (FY) |
2005 – 2007
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| Keywords | wave groups / irregular waves / standing waves / field observation / shallow-water waves |
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| Research Abstract |
In the present study the characteristics of wave groups propagating over the continental shelf toward the coastal region are investigated using the envelopes computed by the Hilbert transform from field observations and related to the evolution of the amplitude and phase modulations. The measurements are performed by 3 wave gauges located over a few lengths of typical wind wave groups, in water of intermediate water depths 0.6<kh <1.2 with k being the wavenumber of significant wave and h being the water depth. During the observation period, the significant wave height exceeds 3m for four days due to the passing of typhoon. It has been observed that the distribution of waves in a group approaching a shore becomes more uniform at the wave growth and wave decay stages of these high waves. During theca periods the significant wave height tends to decrease with approaching the coastal zone.
We have extended the work of Longuet-Higgins and Phillips (1962) to present the expression for changes in phase speed of one wavetrain in the presence of another in water of finite depth. It is shown that the change in phase speed is more pronounced when the directions of two wavetrains are opposite and the wavenumber of another wavetrain is relatively small. The third-other interactions between the normal incident and reflected wave fields due to a vertical wall are investigated by numerical simulations based on Zakharo's equations with kernel functions valid for the cases of finite depth.
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Research Products
(26 results)
