 
Summary: Effect of sidewall conductance on heattransport measurements for turbulent
RayleighBeŽnard convection
Guenter Ahlers
Department of Physics and iQUEST, University of California, Santa Barbara, California 93106
Received 31 July 2000; published 27 December 2000
For measurements of turbulent heat transport in RayleighBeŽnard convection the correction for the sidewall
conductance is usually neglected or based on measurements or estimates for the empty cell. It is argued that the
lateral thermal coupling between the fluid and the wall can invalidate these approaches, and that corrections
based on calculations of the twodimensional temperature fields are required in some cases. These corrections
can increase obtained from fits of N N 0R (R is the Rayleigh number to the Nusselt number N(R) by
0.02 or more, yielding values in the range 0.30 to 0.33, which are larger than most theoretical predictions.
DOI: 10.1103/PhysRevE.63.015303 PACS number s : 47.27. i, 44.25. f, 47.27.Te
One of the important issues in turbulent convection of a
fluid heated from below is the global heat transport of the
system 1 , as expressed by the Nusselt number
N ef f / ; ef f qL/ T. 1
Here q is the heatcurrent density, L the sample height, T
Th Tc the temperature difference, and the conductivity
of the quiescent fluid. Usually a powerlaw
N N0R 2
