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Titel |
Asymmetry of wind waves studied in a laboratory tank |
VerfasserIn |
I. A. Leykin, M. A. Donelan, R. H. Mellen, D. J. McLaughlin |
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 ; 2, no. 3/4 ; Nr. 2, no. 3/4, S.280-289 |
Datensatznummer |
250000260
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Publikation (Nr.) |
copernicus.org/npg-2-280-1995.pdf |
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Zusammenfassung |
Asymmetry of wind waves was studied in laboratory tank tinder
varied wind and fetch conditions using both bispectral analysis of wave records and
third-order statistics of the surface elevation. It is found skewness S (the normalized
third-order moment of surface elevation describing the horizontal asymmetry waves) varies
only slightly with the inverse wave u*/Cm (where u* is the air friction velocity and
Cm is
phase speed of the dominant waves). At the same time asymmetry A, which is determined from
the Hilbert transform of the wave record and characterizes the skewness of the rate of
change of surface elevation, increase consistently in magnitude with the ratio u*/Cm. This
suggests that nonlinear distortion of the wave profile determined by the degree of wind
forcing and is a sensitive indicator of wind-wave interaction processes. It is shown that
the asymmetric profile of waves can described within the frameworks of the nonlinear
nonspectral concept (Plate, 1972; Lake and Yuen, 197 according to which the wind-wave
field can be represented as a coherent bound-wave system consisting mainly of dominant
component w. and its harmonics propagating with the same speed C. , as observed by
Ramamonjiaris and Coantic (1976). The phase shift between o). harmonics is found and shown
to increase with the asymmetry of the waves. |
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