title: Plume motion and large-scale circulation in a cylindrical Rayleigh-Bénard cell.
abstract: We used the time correlation of shadowgraph images to determine the angle Theta of the horizontal component of the plume velocity above (below) the center of the bottom (top) plate of a cylindrical Rayleigh-Bénard cell of aspect ratio Gamma identical with D/L=1 (D is the diameter and L approximately 87 mm is the height) in the Rayleigh-number range 7 x 10(7)</=R</=3 x 10(9) for a Prandtl number sigma=6. We expect that Theta gives the direction of the large-scale circulation. It oscillates time periodically. Near the top and bottom plates Theta(t) has the same frequency but is anticorrelated.
authors.affiliation: Department of Physics and iQUEST, University of California, Santa Barbara, California 93106, USA.
authors.forename: Denis
authors.initials: D
authors.lastname: Funfschilling
authors.forename: Guenter
authors.initials: G
authors.lastname: Ahlers