Apparatus for the Study of Rayleigh-Bénard Convection in Gases
Under Pressure
Apparatus for the Study of Rayleigh-Bénard Convection in Gases
Under Pressure
Review of Scientific Instruments, 67, 2043 (1996).
John R. de Bruyn
Department of Physics, Memorial University of Newfoundland,
St. John's, Newfoundland, Canada A1B 3X7
Eberhard Bodenschatz
Department of Physics and
Laboratory of Atomic and Solid State Physics,
Cornell University
Ithaca, New York 14853.
Stephen W. Morris
Department of Physics and Erindale College
University of Toronto
60 St. George St.,
Toronto, Ontario, Canada M5S 1A7
Steven P. Trainoff
Department of Physics and Center for Nonlinear Science,
University of California
Santa Barbara, California 93106-9530
Yuchou Hu
Department of Physics and Center for Nonlinear Science,
University of California,
Santa Barbara, California 93106-9530 and Center for Nonlinear Studies and Material Science and Technology Division,
Los Alamos National Laboratory,
Los Alamos, New Mexico 87545.
David S. Cannell and Guenter Ahlers
Department of Physics and Center for Nonlinear Science,
University of California
Santa Barbara, California 93106-9530
We review the history of experimental work on Rayleigh-Bénard
convection in gases, and then describe a modern apparatus which has
been used in our experiments on gas convection. This system allows the
study of patterns in a cell with an aspect ratio (cell radius/fluid
layer depth) as large as 100, with the cell thickness uniform to a
fraction of a micron, and with the pressure controlled at the level of
one part in 105. This level of control can yield a stability of the
critical temperature difference for the convective onset of better
than one part in 104. The convection patterns are visualized and the
temperature field can be inferred using the shadowgraph technique. We
describe the flow visualization and image processing necessary for
this. Some interesting results obtained with the system are briefly
summarized.
