Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network

  Advanced Search  

Dynamics of fluctuations in a fluid below the onset of Rayleigh-Benard convection Jaechul Oh,1

Summary: Dynamics of fluctuations in a fluid below the onset of Rayleigh-BeŽnard convection
Jaechul Oh,1
JoseŽ M. Ortiz de ZaŽrate,2
Jan V. Sengers,3
and Guenter Ahlers1
Department of Physics and iQUEST, University of California, Santa Barbara, California 93106, USA
Departamento de FiŽsica Aplicada I, Facultad de FiŽsica, Universidad Complutense, 28040 Madrid, Spain
Institute for Physical Science and Technology, and Departments of Chemical Engineering and Mechanical Engineering,
University of Maryland, College Park, Maryland 20742, USA
Received 1 September 2003; published 23 February 2004
We present experimental data and their theoretical interpretation for the decay rates of temperature fluctua-
tions in a thin layer of a fluid heated from below and confined between parallel horizontal plates. The
measurements were made with the mean temperature of the layer corresponding to the critical isochore of
sulfur hexafluoride above but near the critical point where fluctuations are exceptionally strong. They cover a
wide range of temperature gradients below the onset of Rayleigh-BeŽnard convection, and span wave numbers
on both sides of the critical value for this onset. The decay rates were determined from experimental shadow-
graph images of the fluctuations at several camera exposure times. We present a theoretical expression for an


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


Collections: Physics