2003 Fiscal Year Final Research Report Summary
A new formulation of the spectral dissipation source term for wind-wave modeling
| Project/Area Number |
14550510
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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 | Niigata University |
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Principal Investigator |
IZUMIYA Takashi NIIGATA UNIVERSITY, Faculty of Engineering, Professor, 工学部, 教授 (60151429)
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| Project Period (FY) |
2002 – 2003
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| Keywords | wind waves / energy dissipation rate / similarity structure / turbulent boundary layer / atmospheric input / equilibrium range / degree of saturation / ocean wave prediction |
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| Research Abstract |
Most wind wave models have used the spectral energy balance equation including three forcing terms, atmospheric input source term, resonant nonlinear wave-wave interaction term and energy dissipation term by breaking. Many researchers have made extensive efforts to develop reasonable parameterizations of input source term and nonlinear wave-wave interaction. However, because of the extreme difficulties involved in observing wave breaking and wave-turbulence interactions, energy dissipation rate in wind waves has not been well understood. In the present study, atmospheric input sources, wind-wave spectra and turbulent velocity components under wind waves that played an important role to the wind wave evolution were measured to investigate the spectral similarity of turbulent velocities. A spectral dissipation source term was modeled by using the experimental results and the idea of spectral saturation parameter. In this model, energy dissipation rates were assumed to be proportional to the 3rd power of the orbital velocity components with frequency f and were evaluated by using the newly defined spectral saturation. As a result, spectral dissipation rates in the equilibrium range were shown to be proportional to the 3/2 power of the directional spectrum and the -3^<rd> power of the frequency.
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