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Principle of Maximum Entropy Applied to Rayleigh-Bénard Convection

Takafumi Kita
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Abstract

A statistical-mechanical investigation is performed on Rayleigh-Bénard convection of a dilute classical gas starting from the Boltzmann equation. We first present a microscopic derivation of basic hydrodynamic equations and an expression of entropy appropriate for the convection. This includes an alternative justification for the Oberbeck-Boussinesq approximation. We then calculate entropy change through the convective transition choosing mechanical quantities as independent variables. Above the critical Rayleigh number, the system is found to evolve from the heat-conducting uniform state towards the convective roll state with monotonic increase of entropy on the average. Thus, the principle of maximum entropy proposed for nonequilibrium steady states in a preceding paper is indeed obeyed in this prototype example. The principle also provides a natural explanation for the enhancement of the Nusselt number in convection.

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Takafumi Kita. 2007-01-16. Principle of Maximum Entropy Applied to Rayleigh-Bénard Convection. https://doi.org/10.1143/jpsj.75.124005

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