Flows in non-spherical planetary fluid cores: Analytical and numerical model

Abstract

The interface between the fluid core and the solid mantle of a rapidly rotating planet is usually non-spherical, and the boundary layers in the vicinity of the interface are critical for understanding viscous dissipations and dynamical state of the planet. We shall consider an analytical and a numerical model for understanding how coupling processes between the core and mantle, through the effect of non-spherical interface and non-uniform rotation, affect the flows taking place in planetary fluid cores. Our analytical model is based on the asymptotic analysis of inertial waves and its thin boundary layers using spheroidal coordinates in an ablate rotating spheroid of arbitrary eccentricity. Our numerical model is based on a fully 3D EBE (Element-By-Element) finite element method for a rotating planetary fluid that is confined in an ablate spheroidal cavity of arbitrary eccentricity. Both linear and nonlinear results will be presented and planetary implications will be discussed.