Etude de l'interaction entre le vent et les vagues scélérates

The rogue wave phenomenon, which is of majeur interest for marine safety, cannot be correlated to any specific geophysical phenomenon. Such waves can appear on every ocean of the world, in deep or shallow water, and encounter strong winds in tempest zones. This work aims to study the influence of wind on rogue waves. An experimental approach showed that rogue waves generated by means of energy focusing due to the dispersive nature of water waves, were slightly amplified, that there was a drift of the focusing point, and that their life time was significantly increased. A strong asymmetry is indeed observed between the focusing and defocusing stages. Numerical simulations are performed to analyse, understand, and reproduce the phenomenon. Experiments performed in the air-sea interaction facility are reproduced in a numerical wave tank using boundary integrals method. Miles' mechanism and the modified Jeffreys sheltering mechanism are both considered to model wind action. Jeffreys' sheltering mechanism is modified by introducing a threshold in local slope above which air flow separation occurs over steep crests. Rogue waves can also be generated using another physical mechanism : modulationnal instability of wave fields, or Benjamin-Feir instability. An extension of the study to rogue waves due to modulationnal instability is developed. Numerical simulations of this phenomenon are performed with a pseudo-spectral method. These simulations show that the modified Jeffreys' sheltering mechanism is responsible for a significant increase of the lifetime of those extreme waves, such as for rogue waves due to dispersive focusing. However, the underlying physics are different in both cases. However, these approaches are both based on a linear wind wave coupling, neglecting the influence of waves on the air flow, and based on a potential description of the flow. The existence of a recirculation area (air vortex) observed experimentally above the highest crests can only be simulated correctly when vorticity is taken into account. A numerical method to simulate the rotationnal flow of the two phases viscous fluids, separated by an interface, is introduced.

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Source https://theses.hal.science/tel-00703258
Author Touboul, Julien
Maintainer CCSD
Last Updated May 16, 2026, 09:37 (UTC)
Created May 16, 2026, 09:37 (UTC)
Identifier tel-00703258
Language fr
Rights https://about.hal.science/hal-authorisation-v1/
contributor Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE) ; Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
creator Touboul, Julien
date 2007-11-23T00:00:00
harvest_object_id 6342259c-9077-459f-a2c6-38e8480e0161
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-05-14T00:00:00
set_spec type:THESE