A NUMERICAL MODEL FOR REFRACTION COMPUTATION OF IRREGULAR WAVES DUE TO TIME-VARYING CURRENTS AND WATER DEPTH

Masataka Yamaguchi, Yoshio Hatada

Abstract


This paper presents two models for current-depth refraction of directional spectra due to time-varying currents and water depth, in which a piecewise ray method and a full ray method are used for numerical computations respectively. The results computed by the piecewise ray model in the cases of time-varying one-dimensional and two-dimensional currents are in reasonable agreement with those by the full ray model, which gives the almost exact solution in the case of linear current and water depth variations, except for a slight difference during the phase of strong opposing currents. The computations indicate that time-dependency of currents gives rise to a phase difference between wave height and current variations, and reduction in the amplification effect of directional spectrum due to opposing currents in comparison with steady current case.

Keywords


numerical model; refraction; refraction computation; irregular waves; time-varying current; current; time varying depth

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