Dr. Janet Scheel, Ph.D.
Currently an Assistant Professor of Physics at Occidental College
Assistant Professor of Physics, 2006-2008
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Dr. Scheel's field of research is nonlinear dynamics and pattern formation. The particular system she studies is rotating Rayleigh-Benard convection. In Rayleigh-Benard convection, a fluid cell is bounded by horizontal parallel plates kept at a constant temperature difference. This leads to a buoyancy-driven instability as the temperature difference increases past a critical value. In non-rotating Rayleigh-Benard convection, the conducting state bifurcates to a convection state consisting of straight, parallel rolls. Then if the aspect ratio (ratio of radius to depth) is large, or if the temperature difference is increased further, these states can bifurcate to spatiotemporal chaotic states.
Dr. Scheel finds it is particularly interesting to study rotating Rayleigh-Benard convection, where the entire cell rotates rigidly about a vertical axis. For large enough rotation rates, a chaotic state known as domain chaos has been found to exist.This state consists of domains of parallel rolls, each of whose particular location and size vary chaotically. Domain chaos is one of the few experimentally known spatiotemporal chaotic states that bifurcates supercritically from a time-independent, spatially uniform state (here the motionless conducting state of the fluid). A supercritical bifurcation is particularly useful to study since the new state evolves continuously out of the old state. A control parameter can characterize this transition. This control parameter measures the strength of the driving above the onset of convection, and is linear in the temperature difference.
Dr. Scheel also performs numerical simulations of experimentally realistic Rayleigh-Benard convection systems. This provides a quantitative link between theory and experiment. She has already used such simulations to resolve a long-standing discrepancy between experiment and theory about the domain chaos state of large aspect ratio, rotating Rayleigh-Benard convection.