Large-Scale Flow Characterization in a Rayleigh-Bénard Convective Pattern

Abstract

Theoretical studies of Rayleigh-Bénard convective patterns have shown that the first nonlinear term leading to a nonvariational behaviour corresponds to a spatial harmonic with a vanishing wave number; that is to say a large-scale flow. We confirm experimentally the existence of such a flow, that we have been able to measure for the first time, using a photochromic technique. We establish the relation between the flow profile and the structure distortion.