On the interaction between fronts and vortices

Thibault Jougla (1, 2) , Jo-Hendrik Thysen (1) , Jan-Bert Flór (2)

1 University of St Andrews [Scotland]
2 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]

We investigate the formation and evolution of fronts and vortices in a two-layer stably-stratified fluid experiment. In a rotating tank with a differentially rotating rigid lid, we create a vertical shear across a density interface resulting in a baroclinic front. Different instabilities, such as baroclinic, Kelvin-Helmoltz or Rossby-Kelvin instabilities (RK), appear depending on the regime in Froude, Rossby and dissipation numbers. In the mean time, vortices naturally form that interact with the front. Using space-time analyses and Fourier filter analyses on particle Image Velocimetry (PIV) measurements and dye observations (LIF) for the RK and baroclinic unstable regimes, we investigate the interaction between small-waves with the baroclinic life cycle and the formation of these vortices. We characterise their size, the lifetime and the behaviour of vortices depending on the initial flow parameters.

Domaines: Océan, Atmosphère; Astrophysique [astro-ph]; Planète et Univers [physics]

Thibault Jougla, Jo-Hendrik Thysen, Jan-Bert Flór. On the interaction between fronts and vortices. EGU, Vienne, NP6.2: Recent developments in Geophysical Fluid Dynamics: Waves, Turbulence, Transport and Intermittency, Apr 2018, Vienne, Austria. pp.15435. ⟨hal-02053393⟩