Side wall effects in Rayleigh Bénard experiments

Abstract

In Rayleigh Bénard experiments, the side wall conductivity is traditionally taken into account by subtracting the empty cell heat conductivity from the measured one. We present a model showing that the correction to apply could be considerably larger. We compare to experiments and find good agreement. One of the consequences is that the Nusselt behavior for $Ra< 10^{10}$ could be closer to $Nu \propto Ra^{1/3}$ than currently assumed. Also, the wall effect can appear as a continuous change in the γ exponent $Nu \propto Ra^{\gamma}$