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Titel |
Nonlinear dynamics of wind waves: multifractal phase/time effects |
VerfasserIn |
R. H. Mellen, I. A. Leykin |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 1, no. 1 ; Nr. 1, no. 1, S.51-56 |
Datensatznummer |
250000057
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Publikation (Nr.) |
copernicus.org/npg-1-51-1994.pdf |
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Zusammenfassung |
In addition to the bispectral coherence method, phase/time
analysis of analytic signals is another promising avenue for the investigation of phase
effects in wind waves. Frequency spectra of phase fluctuations obtained from both sea and
laboratory experiments follow an F-β power law over several decades, suggesting that a
fractal description is appropriate. However, many similar natural phenomena have been
shown to be multifractal. Universal multifractals are quantified by two additional
parameters: the Lévy index 0 < α < 2 for the type of multifractal and the co-dimension
0 < C1 < 1 for intermittence. The three parameters are a full statistical measure the nonlinear dynamics. Analysis of laboratory flume data is reported here and the results indicate that the phase fluctuations are 'hard
multifractal' (α > 1). The actual estimate is close to the limiting value
α = 2, which is consistent with Kolmogorov's lognormal model for turbulent fluctuations. Implications for radar and sonar backscattering from the sea surface are briefly considered. |
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