Stability and Transition of Natural Convection Flow in Inclined Cavities
报告人：Prof. Steven Armfield
报告人单位：University of Sydney
讲座内容：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. Recent work on inclined cavities has identified two new transitions, one an unsteady transition associated with travelling waves circulating around the cavity, and the other a steady transition to a three-dimensional as a result of the formation of streamwise vortices structure. Both transitions are shown to be a result of the change in the structure of the outflow intrusions at the downstream ends of the heated and cooled natural convection boundary layers.
报告人简介：Steven 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, Cambridge University, Saitama University, Tohoku University and Auckland University. His research is focused on stability, transition and mixing in buoyant and stratified flows.