Séminaire LMFA (présentiel INSA) : Geostrophic turbulence and the formation of large scale structure par Edgar Knobloch, University California Berkeley

Rotating convection is a prototypical system at the core of geophysical fluid dynamics. However, the parameter values for geophysical flows take values that are far outside those that can be studied in the laboratory or via state of the art numerical simulations. In this talk I will describe a formal asymptotic procedure that leads to a reduced system of equations valid in the limit of very strong rotation. These equations describe four regimes as the Rayleigh number Ra increases : a disordered cellular regime near threshold, a regime of weakly interacting convective Taylor columns at larger Ra, followed for yet larger Ra by a breakdown of the convective Taylor columns into a disordered plume regime characterized by reduced heat transport efficiency, and finally by a new type of turbulence called geostrophic turbulence.