Consulta: creatorFacets:"Perrot, Xavier"
Registros recuperados: 5
Data/hora: 07/06/2024 09:16:17

Instability of a two-step Rankine vortex in a reduced gravity QG model
Provedor de dados: 5
Autores: Perrot, Xavier; Carton, Xavier.
We investigate the stability of a steplike Rankine vortex in a one-active-layer, reduced gravity, quasi-geostrophic model. After calculating the linear stability with a normal mode analysis, the singular modes are determined as a function of the vortex shape to investigate short-time stability. Finally we determine the position of the critical layer and show its influence when it lies inside the vortex.
Tipo: Text
Palavras-chave: Vortex dynamics; Instability; Normal/Singular modes; Critical layer.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00202/31360/31183.pdf

Explosive instability of geostrophic vortices. Part 1: baroclinic instability
Provedor de dados: 5
Autores: Carton, Xavier; Flierl, Glenn R.; Perrot, Xavier; Meunier, Thomas; Sokolovskiy, Mikhail.
In a quasi-geostrophic model, we study the baroclinic instability of a two-layer vortex. The singular unstable modes for potential vorticity anomalies are compared with the classical normal modes. Short-time singular modes are explosively unstable and, at short times, depend only on the baroclinic component of the flow. As time progresses, they evolve towards the normal modes and their sensitivity to flow parameters is explored. Asymptotic solutions are provided.
Tipo: Text
Palavras-chave: Quasi-geostrophic equations; Inviscid flows; Vortex stability; Normal or singular modes; Parametric resonance.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00002/11352/7925.pdf

Explosive instability of geostrophic vortices. Part 2: parametric instability
Provedor de dados: 5
Autores: Carton, Xavier; Meunier, Thomas; Flierl, Glenn R.; Perrot, Xavier; Sokolovskiy, Mikhail.
In a two-layer quasi-geostrophic model, a baroclinic vortex is submitted to a periodic forcing of its mean baroclinic azimuthal velocity. It is shown that parametric effects could stabilize a vortex which is baroclinically unstable in the absence of forcing. Conversely, parametric resonance can destabilize a baroclinically stable vortex, under conditions on the vortex parameters, on the ratio of layer thicknesses or on the forcing frequency.
Tipo: Text
Palavras-chave: Quasi-geostrophic equations; Inviscid flows; Vortex stability; Parametric resonance.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00002/11353/7926.pdf

2D vortex interaction in a non-uniform flow
Provedor de dados: 5
Autores: Perrot, Xavier; Carton, Xavier.
In a two-dimensional incompressible fluid, we study the interaction of two like-signed Rankine vortices embedded in a steady shear/strain flow. The numerical results of vortex evolutions are compared with the analytical results for point vortices. We show the existence of vortex equilibria, and of merger for initial distances larger than those without external flow. The evolutions depend on the initial orientation of the vortices in the external flow.
Tipo: Text
Palavras-chave: Two-dimensional incompressible flows; Vortex merger; Pseudo-spectral model.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/2009/publication-7442.pdf

Integrable motion of a vortex dipole in an axisymmetric flow
Provedor de dados: 5
Autores: Sutyrin, G; Perrot, Xavier; Carton, Xavier.
The evolution of a self-propelling vortex dipole, embedded in an external nondivergent flow with constant potential vorticity, is Studied in an equivalent-barotropic model commonly used in geophysical, astrophysical and plasma studies. In addition to the conservation of the Hamiltonian for an arbitrary point vortex dipole, it is found that the angular momentum is also conserved when the external flow is axisymmetric. This reduces the original four degrees of freedom to only two, so that the solution is expressed in quadratures. In particular, the scattering of antisymmetric dipoles approaching from the infinity is analyzed in the presence of an axisymmetric oceanic flow typical for the vicinity of isolated seamounts.
Tipo: Text
Palavras-chave: Quasi geostrophic; Topography interaction; Rotating fluids; Vortex dynamics.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-7320.pdf