Statistics of local temperature dissipation in high rayleigh number convection

Abstract

We study the statistics of the local temperature dissipation in high Rayleigh number convection. We find that its probability distribution deviates from a lognormal, although very low order moments can be approximated by a lognormal distribution. Instead, the moments satisfy a hierarchy similar to that proposed by She and Leveque [Phys. Rev. Lett. 72, 336 (1994)] for the local energy dissipation. Moreover, the moments scale with the separation time. No change in the scaling behavior is observed when the Bolgiano scale is crossed, indicating that the statistics have the same nature in the buoyancy-driven and the inertia-driven regimes.