Interaction of flows driven by tides and precession with convection in planets and stars

The discovery of several thousand planets orbiting stars other than the Sun is the most exciting development in modern astrophysics. Many orbit their stars very closely in a few Earth days, and the gravitational tidal interactions between these planets and their stars deform the planet (and star) into an ellipsoidal shape and excite internal tidal flows. The dissipation of these flows can drive long-term evolution of the planetary(and stellar) spin and orbit over millions/billions of years, but remains poorly understood. This project will study instabilities of axially-precessing flows (excited in a planet with a spin axis that is misaligned with respect to the orbit normal) and/or instabilities of elliptical flows, and their interaction with turbulent convection. These instabilities have previously been invoked in convective regions of planets and stars but have been studied without modelling the effects of convection directly. This project will involve hydrodynamical simulations in local Cartesian models (that represent a small patch of a planet or star), and if time permits, in global spherical/ellipsoidal models, to study the interaction of these instabilities. Flows driven by axial precession have also been proposed as an unconventional way to generate magnetic fields in planetary cores.