MAE Seminar: Convection beyond Rayleigh and Bénard

Abstract: Rayleigh–Bénard convection is a canonical flow in fluid mechanics, with applications in industry, geophysics, astrophysics and beyond. Investigations have examined linear and nonlinear stability as well as deriving analytical bounds on quantities of interest, while laboratory and numerical experiments have given insight into the behavior at large Rayleigh numbers. Generalizations such as the case of convection in porous media, as well as the effect of rotation and magnetic fields, can be found in textbooks. In this talk I will discuss some less well-known cases. First, periodically-driven convection, in which the temperature along one boundary varies periodically in time. This provides a model for heating of the waters of Lake Superior in Spring. Second, horizontal convection, in which the temperature (or buoyancy) varies along a horizontal boundary. This case offers a simplified model for e.g., large-scale oceanic flows induced by horizontal buoyancy gradients. I will review previous known results and present recent work on the stability and behavior of these flows. 

Bio: Stefan G. Llewellyn Smith is the chair of mechanical and aerospace engineering at UCSD. He received his Ph.D. in applied mathematics from the University of Cambridge in 1996. He was a research fellow of Queens' College, Cambridge, from 1996 to 1999, working in the Department of Applied Mathematics and Theoretical Physics. He spent a year from 1996 to 1997 on a Lindemann Trust Fellowship at the Scripps Institution of Oceanography in La Jolla. He joined the Department of Mechanical and Aerospace Engineering at UCSD in 1999 as assistant professor of environmental engineering. His research interests include fluid dynamics, especially its application to environmental and engineering problems, acoustics and asymptotic methods.