Layering in geophysical fluid dynamics systems

A fascinating feature of many geophysical fluid dynamical systems is their tendency to form layers or "staircases", in which a key physical quantity (e.g., density) exhibits a staircase structure with depth. This can happen, for example, in forced turbulence, in double-diffusive convection (leading to oceanographic thermohaline staircases) and in rotating flows (leading to the potential vorticity staircases manifested by the jets on Jupiter).
The project will address fundamental questions in the layering process through idealised numerical simulations. It will concentrate on two-dimensional fluid flows, which are relatively easy to simulate and provide the high resolution needed to examine layer structure. It will first investigate forced flows in a stratified fluid, with particular emphasis on determining the properties of the forcing that do (and do not) lead to layering, and in determining the parameter regimes where layering can occur. It will then turn to the problem of double-diffusive layering. Of particular interest is to determine exactly what happens in the thin interfaces, and how these are connected to the fluid flow in the broader layers. All the results obtained will be analysed in terms of their relation both to oceanographic and experimental observations and to existing reduced models of the layering process.