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| Guimarães, Pedro Veras; Ardhuin, Fabrice; Bergamasco, Filippo; Leckler, Fabien; Filipot, Jean-francois; Shim, Jae-seol; Dulov, Vladimir; Benetazzo, Alvise. |
| Stereo imaging of the sea surface elevation provides unique field data to investigate the geometry and dynamics of oceanic waves. Typically, this technique allows retrieving the 4-D ocean topography (3-D space + time) at high frequency (up to 15–20 Hz) over a sea surface region of area ~104 m2. Stereo data fill the existing wide gap between sea surface elevation time-measurements, like the local observation provided by wave-buoys, and large-scale ocean observations by satellites. The analysis of stereo images provides a direct measurement of the wavefield without the need of any linear-wave theory assumption, so it is particularly interesting to investigate the nonlinearities of the surface, wave-current interaction, rogue waves, wave breaking, air-sea... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00631/74285/73895.pdf |
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| Peureux, Charles; Ardhuin, Fabrice; Guimarães, Pedro Veras. |
| The wave action equation provides a general framework that has been applied to the conservative hydrodynamic interactions between short and long surface waves. So far, only a limited range of solutions have been investigated. Here we show that the wave action equation predicts that groups of short waves propagating over long monochromatic waves are unstable. We demonstrate theoretically and numerically a new ratchet‐type instability that progressively condenses short wave action around the long wave crests due to the correlation of phase speed and action fluctuations. This instability is of particular interest because it may lead to a higher probability of breaking for short waves propagating in directions within ±35 degrees of the dominant waves... |
| Tipo: Text |
Palavras-chave: Instability; Modulation; Wind waves. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00661/77318/83369.pdf |
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