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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 investigate numerically the nonlinear interactions between hetons. Hetons are baroclinic structures consisting of two vortices of opposite sign lying at different depths. Hetons are long-lived. They most often translate (they can sometimes rotate) and therefore they can noticeably contribute to the transport of scalar properties in the oceans. Heton interactions can interrupt this translation and thus this transport, by inducing a reconfiguration of interacting hetons into more complex baroclinic multipoles. More specifically, we study here the general case of two hetons, which collide with an offset between their translation axes. For this purpose, we use the point vortex theory, the ellipsoidal vortex model and direct simulations in the... |
| Tipo: Text |
Palavras-chave: Baroclinic flows; Geophysical and geological flows; Quasi-geostrophic flows. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44401/44157.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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| De Marez, Charly; Carton, Xavier; Morvan, Mathieu; Reinaud, Jean N.. |
| We study the influence of bottom topography on the interaction of two identical vortices in a two-layer, quasi-geostrophic model. The two vortices have piecewise-uniform potential vorticity and are lying in the upper layer of the model. The topography is a smooth bottom slope. For two cyclones, topography modifies the merger critical distance and the merger efficiency: the topographic wave and vortices can advect the two cyclones along the shelf when they are initially far from it or towards the shelf when they are initially closer to it. They can also advect the two cyclones towards each other and thus favour merger. The cyclones deform, and the potential vorticity field undergoes filamentation. Regimes of partial vortex merger or of vortex splitting are... |
| Tipo: Text |
Palavras-chave: Vortex interaction; Topography; Quasi-geostrophic model. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00600/71250/69625.pdf |
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