Generation of Gravity-Capillary Wind Waves by Instability of a Coupled Shear-Flow

Autor: Malek Abid, Christian Kharif, Hung-Chu Hsu, Yang-Yih Chen
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of Marine Science and Engineering, Vol 10, Iss 1, p 46 (2022)
Druh dokumentu: article
ISSN: 2077-1312
DOI: 10.3390/jmse10010046
Popis: The theory of surface wave generation, in viscous flows, is modified by replacing the linear-logarithmic shear velocity profile, in the air, with a model which links smoothly the linear and logarithmic layers through the buffer layer. This profile includes the effects of air flow turbulence using a damped mixing-length model. In the water, an exponential shear velocity profile is used. It is shown that this modified and coupled shear-velocity profile gives a better agreement with experimental data than the coupled linear-logarithmic, non smooth profile, (in the air)–exponential profile (in the water), widely used in the literature. We also give new insights on retrograde modes that are Doppler shifted by the surface velocity at the air-sea interface, namely on the threshold value of the surface current for the occurrence of a second unstable mode.
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