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| Reinaud, Jean N.; Carton, Xavier. |
| We examine the interactions between two three-dimensional quasi-geostrophic hetons. The hetons are initially translating towards one another. We address the effect of the vertical distance between the two poles (vortices) constituting each heton on the interaction. We also examine the influence of the horizontal separation between the poles within each heton. In this investigation, the two hetons are facing each other. Two configurations are possible depending on the respective locations of the like-signed poles of the hetons. When they lie at the same depth, we refer to the configuration as symmetric; the antisymmetric configuration corresponds to opposite-signed poles at the same depth. The first step in the investigation uses point vortices to represent... |
| Tipo: Text |
Palavras-chave: Geophysical and geological flows; Quasi-geostrophic flows; Vortex dynamics. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00277/38796/37470.pdf |
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| Reinaud, Jean N.; Carton, Xavier. |
| We consider the interaction between two quasi-geostrophic vortices of height-to-width aspect ratio h/r, lying at two different vertical levels. We investigate whether such structures naturally align. In the case the vortices occupy distinct yet contiguous vertical levels, such an alignment can contribute to the growth in volume of oceanic mesoscale vortices. The other growth mechanism is the merger of vortices sharing common vertical levels. We show that there exist titled equilibrium states where vortices nearly align slantwise. Most equilibria for prolate vortices (h/r>1) are stable apart in a very narrow region of the parameter space. The instability is however normally non-destructive. Pairs of oblate vortices may also be in an unstable equilibria... |
| Tipo: Text |
Palavras-chave: Vortex dynamics; Vortex alignment; Quasi-geostrophy. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71259/69643.pdf |
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| Reinaud, Jean N.; Carton, Xavier; Dritschel, David G.. |
| We investigate the interaction between a heton and a current generated by a filament of buoyancy anomaly at the surface. Hetons are baroclinic dipoles consisting of a pair of vortices of opposite signs lying at different depths. Such structures have self-induced motion whenever the pair of vortices are offset horizontally. A surface buoyancy filament generates a shear flow since the density perturbation locally modifies the pressure field. The vertical shear induced by the filament offsets the vortices of the heton if vertically aligned initially. Moreover, if the vortex nearer the surface is in adverse horizontal shear with the buoyancy filament, the heton tends to move towards the filament. Conversely, if the upper vortex is in cooperative horizontal... |
| Tipo: Text |
Palavras-chave: Quasi-geostrophy; Surface buoyancy anomaly; Vortex dynamics. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00600/71253/69631.pdf |
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| 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 |
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