INERTIAL EFFECTS ON RECURRENT PATTERN-FORMATION IN PERIODICALLY DRIVEN RAYLEIGH-BENARD CONVECTION

Periodically driven Rayleigh-Benard convection is modelled by a vertic al mode expansion of a mean field approximation to the Oberbeck-Boussi nesq equations with thermal noise. The resulting model generalizes the Lorenz Model introduced by Ahlers, Hohenberg, and Lucke [Phys. Rev. A 32 (1985) 3493] including the continuous dependence on the horizontal wavenumber. The model is used to predict the order-disorder transitio n experimentally observed in the recurrent pattern formation near the convective onset, showing that the inclusion of inertial effects in th e description of externally modulated pattern forming transitions, lea ds to theoretical predictions for the effects of thermal noise much cl oser to the experimental results than those of previous (purely dissip ative) models. (C) 1998 Elsevier Science B.V. All rights reserved.