Orateur
Description
Co-authors: Michael Le Bars, Clement Audefroy
Abstract: Motivated by planetary science, we examine the stability of flows with both buoyancy gradients on horizontal boundaries and vertical buoyancy fluxes entering the domain, hence combining aspects of horizontal convection (HC) and Rayleigh–Bénard (RB) convection. Exact steady states exist in the form of shear flows. Unlike the case of RB and classical shear flow stability, the principles of exchange of stability and Squire's theorem no longer hold, so that the marginal modes are no longer two-dimensional with zero frequency. We explore the stability boundary numerically in the horizontal/vertical Rayleigh number/Prandlt number parameter space. Using scaling arguments, we identify different families of modes: RB modes, central shear modes for small Prandtl numbers, boundary-trapped shear modes and 3D baroclinic modes.