1990 Fiscal Year Final Research Report Summary
Study on Numerical Models of Nearshore Currents Including Wave Nonlinearity or Wave Irregularity
| Project/Area Number |
01550408
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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 |
YAMAGUCHI Masataka Ehime Univ. Faculty of Eng. Prof., 工学部, 教授 (60027266)
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| Co-Investigator(Kenkyū-buntansha) |
IFUKU Makoto Ehime Univ. Faculty of Eng. Lecturer., 工学部, 講師 (20108400)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Finite amplitude waves / Irregular waves / Nonlinear long waves / Wave transformation model / Nearshore current model / Characteristic method / Finite difference model |
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| Research Abstract |
The conclusions of this study are as follows ;
(1) Mathematical proof is given that the interrelation among the existing cnoidal wave theories is such that the Chapppelear theory includes the other theories.
(2) Wave shoaling and refraction due to current-depth variations are analyzed with use of higher order solutions of Stokes and cnoidal waves.
(3) Two models of wave transformation and nearshore currents in which wave characteristics are estimated with Stokes or cnoidal wave theory are established.
(4) One-dimensional and two-dimensional models of wave transformation are developed on the basis of characteristics solution for nonlinear long wave equations. These models are also applicable to the computation of transformation of irregular waves.
(5) A model for refraction computation of irregular waves due to time-varying currents and water depth is established on the basis of conservation of wave action spectral density. Numerical computation shows that time-dependency of currents gives rise to reduction in the amplification effect of directional spectrum due to opposing currents.
(6) A model of nearshore currents induced by irregular waves in the presence of coastal structures is completed, in which the effect of diffraction and reflection are evaluated with approximate ways. The model reasonably explains the experimental data of wave transformation and the formation of curent patterns appropriate to their configuration of structures.
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Research Products
(36 results)
