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Indexed by:期刊论文
Date of Publication:2014-12-01
Journal:COASTAL ENGINEERING
Included Journals:SCIE、EI、Scopus
Volume:94
Page Number:23-32
ISSN No.:0378-3839
Key Words:Shallow water; Random waves; Nonlinear interaction; Wavelet-based bispectrum; Parameterization
Abstract:Investigation of the bottom slope effects on the nonlinear transformation of irregular waves, which are generated based on JONSWAP spectra, is carried out in a physical wave flume with three slopes (beta = 1/15,1/30, 1/45). The slope effects on the estimation of representative wave height are examined first. To obtain a better estimation of wave height, the slope effect should be considered when slope is larger than 1/30. The nonlinear parameters (bicoherence, skewness and asymmetry) are estimated by using the wavelet-based bispectrum, and the empirical formulae regarding these nonlinear parameters as a function of the local Ursell number are derived based on the present data measured on each slope. The results indicate that the slopes have a negligible effect on the variations of the skewness. The fitted coefficients of the formulae for the other parameters on slope beta = 1/15 are clearly different from the results on the slopes beta = 1/30 and 1/45, indicating that slope influence on the parameterization cannot be ignored when beta > 1/30. Hence, new formulae considering the slope effect are presented. Furthermore, the empirical formulae for the data in surf zone are recommended. (C) 2014 Elsevier B.V. All rights reserved.