Convection, rotation and shear flows in stellar and planetary interiors

Observations of the Sun and giant planets reveal that turbulent convection occurs alongside large-scale shear flows that vary with depth and latitude. Understanding the complex interplay between convection, rotation, and shear flows is therefore essential for deciphering the dynamics of stars and planets. This project will focus specifically on quantifying the influence of large-scale shear flows on convective heat transport in stellar and planetary interiors.

In stars and planets, shear flows may be driven by convection itself or by other processes, such as baroclinic instabilities. Therefore, rather than focusing on the specific mechanisms generating these flows, we will begin by imposing shear flows of different forms to assess their impact on heat transport in rotating convection. This investigation will involve a combination of linear theory and the adaptation of an existing numerical code to solve the full nonlinear problem in both two and three dimensions.

Alongside the numerical simulations, this project aims to improve existing theoretical models of heat transport in rotating convection, which currently do not fully account for the effects of large-scale shear flows. By analysing the impact of specific shear flows in certain regimes, we will extend these models to better reflect realistic stellar and planetary conditions.

Finally, the project will explore whether insights developed for imposed shear flows can be applied to cases where the flows are self-consistently generated within the system.