Effect of sidewall conductance on heat-transport measurements for turbulent Rayleigh-Bénard convection

For measurements of turbulent heat transport in Rayleigh-Bénard 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 two-dimensional temperature fields are required in some cases. These corrections can increase gamma obtained from fits of N=N(0)Rgamma (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.