Turbulence near Onset of Convection

Abstract

New long-term (days) measurements of the evolution of turbulence for a Rayleigh-Bénard system with aspect ratio $\Gamma =4.72\mathrm{}$ reveal a turbulent state, with a threshold near the critical Rayleigh number $R_c$, which consists of a random background time dependence and rare, randomly spaced, major events. These events are discussed in terms of the analog of a particle under the influence of a stochastic driving force and in a potential with two minima.