Summary: J. Fluid Mech., page 1 of 36 c Cambridge University Press 2011
doi:10.1017/S0022112010005963
1
Turbulent Rayleigh­B´enard convection in a
cylindrical container with aspect ratio = 0.50
and Prandtl number Pr = 4.38
STEPHAN WEISS AND GUENTER AHLERS
Department of Physics, University of California, Santa Barbara, CA 93106, USA
(Received 6 September 2010; revised 23 October 2010; accepted 10 November 2010)
Measurements of the Nusselt number and properties of the large-scale circulation
(LSC) are presented for turbulent Rayleigh­B´enard convection in water-filled
cylindrical containers (Prandtl number Pr = 4.38) with aspect ratio = 0.50. They
cover the range 2 × 108 < Ra < 1 × 1011
of the Rayleigh number Ra. We confirm the
occurrence of a double-roll state (DRS) of the LSC and focus on the statistics of the
transitions between the DRS and a single-roll state (SRS). The fraction of the run
time when the SRS existed varied continuously from about 0.12 near Ra = 2 × 108
to about 0.8 near Ra = 1011
, while the fraction of the run time when the DRS could
be detected changed from about 0.4 to about 0.06 over the same range of Ra. We

Source: Ahlers, Guenter - Department of Physics, University of California at Santa Barbara

Collections: Physics