Natural convection flow in a differentially heated square cavity has been widely studied, providing a canonical representation of a large range of buoyancy driven flows. In the standard configuration one sidewall is heated, the opposing sidewall cooled, with all other walls, ceiling and floor adiabatic. The flow consists of natural convection boundary layers forming on the heated/cooled walls, entraining fluid from, and discharging to, the stratified interior. The overall flow acts to transport heat from the heated to the cooled wall, with the details of the flow depending on the temperature difference between the sidewalls, typically characterised by a Rayleigh (or Grashof) number, and on the Prandtl number of the fluid. Start-up, transition and full development have been extensively investigated showing increasingly unsteady and complex behaviour with increasing Rayleigh number. Early results on the basic flow structure and stability properties, together with the nature and Prandtl number dependence of the transition to chaotic flow at full development, will be reviewed. Recent work will be presented on the absolute stability of the flow, together with a new three-dimensional steady turning flow instability in the context of the tilted cavity.

Short Bio: Steve Armfield is Professor of Computational Fluid Dynamics in the School of Aerospace, Mechanical and Mechatronic Engineering at the University of Sydney. He completed his PhD, at the University of Sydney, in 1987, and has held appointments at the University of Western Australia and the University of New South Wales, as well as visiting positions at Stanford University,  Saitama University, Tohoku University and Auckland University. His research is focused on stability, transition and mixing in buoyant and stratified flows.