报告摘要：The problem of thermal convection in rapidly rotating, self-gravitating fluid bodies has been widely modeled in spheres or spherical shells, which implicitly neglects the flattening effect due to the centrifugal force. However, the fast rotation of planets could make them bulge out enough that they can’t be treated as spheres. As a result, investigating the problem of rotating thermal convection in oblate spheroids will help better understand the convective processes in rapidly rotating planets or other more flattened astrophysical systems. The equilibrium shape of a rotating fluid planet under self-gravitation shall be oblate spheroidal rather than spherical due to the centrifugal force. In our previous PR Fluids paper series Paper I – IV [Kong (2022) 7:074803; Li and Kong (2022) 7:103502; Li and Kong (2023) 8:L011501; Li and Kong (2024) 9:113502], the problem of convective instabilities was formulated and tackled for rotationally flattened Boussinesq fluid. Based on the linear onset theory of oblate spheroidal convection, the transition to turbulent convection was systematically explored using fully 3D nonlinear numerical simulations. For a typical asymptotically small Ekman number E = 5e-5 and a moderate Prandtl number Pr = 1.0, this talk shows and discusses that when the rotational flattening effect gets intense, the nice geostrophic feature of convective motion, usually seen in spherical rotating convections, does not maintain anymore at higher Rayleigh numbers. Turbulent convection of equatorial anti-symmetry develops remarkably in the off-equatorial interior.
主讲人简介：Dr. Dali Kong graduated from the Department of Astronomy, Nanjing University, in 2008 and obtained his Ph.D. in Applied Mathematics from the University of Exeter in 2012. He joined Shanghai Astronomical Observatory in 2017 after five years working at the Centre for Geophysical and Astrophysical Fluid Dynamics, University of Exeter. Dr. Kong mainly works in planetary fluid dynamics and is particularly skilled at analyzing the dynamics of rapidly rotating systems.
