Summary: J. Fluid Mech. (2006), vol. 557, pp. 347­367. c 2006 Cambridge University Press
doi:10.1017/S0022112006009888 Printed in the United Kingdom
347
The search for slow transients, and the effect
of imperfect vertical alignment, in turbulent
Rayleigh­B´enard convection
By GUENTER AHLERS, ERIC BROWN
AND ALEXEI NIKOLAENKO
Department of Physics and iQUEST, University of California, Santa Barbara, CA 93106, USA
(Received 26 May 2005 and in revised form 17 November 2005)
We report experimental results for the influence of a tilt angle relative to gravity
on turbulent Rayleigh­B´enard convection of cylindrical samples. The measurements
were made at Rayleigh numbers R up to 1011
with two samples of height L equal to
the diameter D (aspect ratio D/L 1), one with L 0.5 m (the `large' sample)
and the other with L 0.25 m (the `medium' sample). The fluid was water with a
Prandtl number = 4.38.
In contrast to the experiences reported by Chill`a et al. (Eur. Phys. J. B, vol. 40, 2004,
p. 223) for a similar sample but with 0.5 (D = 0.5 and L = 1.0 m), we found no long
relaxation times. For R = 9.4 × 1010

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

Collections: Physics