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10.0 



COMPONENT WAVES 



INDIVIDUAL WAVES 

 ZERO-CROSSING TROUGH-TO-TROUGH 



wavHunn;! ^°"'P^"^°".°f ^"^^-^ ^'-^^ °f normalized energy spectra from the same wind-wave records in the wind 

 wave tunnel. A: Traditional energy spectra by the component-wave model. B: Energy spectra for individual waves 



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spectra, which was obtained from the cross-spectra 

 of the records of two adjacent wave gauges (Figure 

 12) , approximately the same phase speed is obtained 

 in the before-mentioned main frequency range, where 

 the coherence is close to unity. However, in the 

 higher frequency range, it is virtually constant 

 m agreement with Ramamonjiarisoa' s 1974 measurement. 

 The original values are shown in Figure 13 , in 

 which locations of the spectral peak are shown by 

 arrows for the shortest and the longest fetches, 

 respectively, and as the peak frequency moves to 

 the left, the phase speed of the component waves 

 becomes larger. In the figure, the full line shows 



the phase speed of linear waves. Figure 12 is the 

 normalization of Figure 13 , and Figure 14 shows an 

 example of the comparison of phase speeds of com- 

 ponent waves and individual waves . It should be 

 noted that, as the distance of two wave gauges 

 becomes wider, the range of high coherence becomes 

 narrower, and the phase speed of component waves 

 tends to be more uniform and obscure. However, it 

 is at least evident that phase speeds for both com- 

 ponent waves and individual waves have the same 

 value near the peak frequency, and are inversely 

 proportional to the square root of frequency, and 

 much higher than the values of linear waves. It 



