CENTRALE LYON - Postdoc Rotating convection on the tilted f−plane

The Fluid Mechanics and Acoustics Laboratory (LMFA) develops a continuum of research in fluid mechanics and acoustics, from the understanding and the modelling of physical phenomena to applied research, in collaboration with industrial partners and public institutions

Turbulent convection is a key ingredient for planetary and stellar interiors, and for the subsurface oceans of icy-moons. In these celestial bodies, flows are heavily constrained by global rotation and, consequently, operate in a quasi-geostrophic regime characterised by the dominance of the pressure and Coriolis forces. Hallmarks of geostrophic turbulence include a marked anisotropy along rotation (Proudman-Taylor theorem) and the propensity to form large scale structures in the form of vortices or zonal jets.

Rotating Rayleigh-Benard convection (RRBC) is a quintessential paradigm for understanding these flows in a simplified cartesian geometry. The case of aligned gravity and rotation (‘upright’ convection) that pertains to polar regions and has been the focus of many studies, including laboratory experiments, asymptotic models and recent direct numerical simulations reaching realistic rotation rates (see the publication by van Kan, Julien, Miquel, Knobloch, J. Fluid Mech. 2025). Comparatively, the case of misaligned gravity and rotation that pertains to fluid patches at latitudes away from the poles has received much less attention despite its importance for regional parametrization in global spherical models.

Guided by asymptotic models, this work will use direct numerical simulations to analyze rapidly rotating Rayleigh-Benard convection on the tilted f-plane by focussing on the transition to the geostrophic regimes. The case of different fluids, including water and liquid metal, will be considered. The tasks associated with the project will include setting and running numerical simulations using Coral, an in-house high-performance spectral solver written in Fortran; writing scripts in Python (or another equivalent high-level language) for processing and analysing the generated data sets; surveying the relevant literature and reporting progresses in regular group meetings; communicating the results in scientific articles and conferences.