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|Title: ||Pressure transfer function in time and time-frequency domains|
|Authors: ||Min-Chih Huang;Cheng-Han Tsai|
|Contributors: ||NTOU:Department of Marine Environmental Informatics|
|Keywords: ||Pressure transfer function;Fourier transform;SIWEH transform;Wavelet transform;Wind waves|
|Issue Date: ||2011-10-20T08:23:16Z
|Publisher: ||Ocean Engineering|
|Abstract: ||abstract:In this paper, we define a time-domain pressure transfer function calculated from SIWEH (smoothed instantaneous wave energy history) transforms, and a time-frequency domain pressure transfer function calculated from wavelet transforms, of synchronized wave and pressure data. It is our objective to study whether the time-domain pressure transfer function and the time-frequency domain pressure transfer function can provide new interpretation of wind wave behaviors. The detail structure of local time-frequency pressure transfer function in three-dimensional plot from wavelet transform is not employed due to its large variations, instead the time-integral wavelet spectral pressure transfer function and frequency-integral wavelet SIWEH pressure transfer function are used. These two averaged pressure transfer functions are smooth approximations of frequency-domain Fourier and time-domain SIWEH pressure transfer functions, respectively.
Application to real ocean waves reveals that in frequency-domain the measured Fourier and wavelet spectral pressure transfer functions can be approximated by the linear pressure transfer function in the dominant wave range. In time-domain, the wavelet SIWEH pressure transfer function is a better indicator of wind wave behaviors than the SIWEH pressure transfer function. A value higher than 0.5 for the wavelet SIWEH pressure transfer function is a good discriminator of relative shallow-water long waves and wave groups are mostly composed of relative low frequency long waves.
|Relation: ||35(11-12), pp.1203–1210|
|Appears in Collections:||[海洋環境資訊系] 期刊論文|
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