| Summary: | 碩士 === 國立交通大學 === 土木工程學系 === 84 === In the present study an empirical transfer function between
the wave pressure and wave height,which was established by Kuo
and Chiu(1994) ,was applied to predict the history signals of
the free water surface elevation from the wave pressure beneath
the still water level.The Fast Fourier Transform(FFT) method is
used to calculate the power spectral and history signals of
wave height.The FFT method is compared with LCM method
developed by Nielsen(1986) in this paper.It is found that both
of FFT method and LCM method are accurately calculated when the
pressure gages are locatted near the still water level.However,
when the distance between the pressure gage and the still water
level is longer,the FFT method with the empirical transfer
function is more efficient and accurate than the LCM method.
Furtherwore,the present study has decided on the cutoff
frequency range,the weak point of the power spectral analisis
which was resolved in this paper. Furthermore,the present study
used the physical model test to investigate the transfer
function between the wave pressure and the wave height in
shallow water. By the analysis from the experimental data, we
can find the transfer function is concern with the wave
frequency and pressure gage locations. In addition ,the
transfer functions of each older nonlinear components seem to
be the same.
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