| Project/Area Number |
13650567
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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, Department of Architecture and Civil Engineering, Professor, 大学院・工学研究科, 教授 (10135402)
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| Co-Investigator(Kenkyū-buntansha) |
KITANO Toshikazu Nagoya Institute of Technology, Department of Architecture and Civil Engineering, Associate Professor, 工学部, 助教授 (00284307)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Wave Group / Nonlinear Wave / Spectral Band / Envelope Wave / Long-Period Wave / Demodulation |
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| Research Abstract |
Evolution of strongly nonlinear wave groups of various initial envelope shapes is investigated experimentally and numerically. Experiments with five different shapes of wave groups are carried out over the bottom slope of 1 : 30. The first wave group consists of a simple bimodal spectrum while the second and third groups have a set of discrete frequencies. The fourth groups are widely separated and have a Gaussian shaped spectrum. The fifth groups consist of a rectangular shaped spectrum. The effective water depth is 0.5m in the vicinity of the wavemaker, so that all the waves propagate over the critical dimensionless water depth kh=1.36. It is found that the wave groups propagating over the slope undergo modulation and subsequent demodulation. For the strongly nonlinear waves, the wave, energy tends to spread more uniformly over the group. The wave groups having the same shape but different spectral components tend to undergo nearly identical evolution of spectra.
The numerical model is based on the third-order Zakharov integral equation. As in the work of Shemer et al. (2001) the Zakharov nonlinear equation is rewritten in the form of spatial Zakharov equation. This spatial Zakharov equation constitutes a reasonable model for shoaling of nonlinear wave groups over a sloping beach, even for the groups having very large initial wave steepness.
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