Some considerations about the symmetry and evolution of chaotic Rayleigh¨CB¨¦nard convection: The flywheel mechanism and the ¡°wind?of turbulence

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• 作者：Marcello  ; Lappa ;   ; ^{marlappa@unina.it}
• 关键词：Computational fluid mechanics ; Thermal convection ; Transitions
• 刊名：Comptes Rendus Mecanique
• 出版年：2011
• 出版时间：September 2011
• 年：2011
• 卷：339
• 期：9
• 页码：563-572
• 全文大小：919 K

文摘

Rayleigh¨CB¨¦nard convection in finite-size enclosures exhibits really intricate features when turbulent states are reached and thermal plumes play a crucial role in a number of them. This complex mechanism may be regarded as a ¡°machine?containing many different working parts: boundary layers, mixing zones, jets, and a relatively free and isothermal central region. These parts are generally regarded as the constitutive ¡°ingredients?whose interplay leads to the emergence of a macroscopic pattern with well-defined properties. Like the Lorenz model (but with the due differences) such a complex structure has a prevailing two-dimensional nature and can be oriented clockwise or anticlockwise (both configurations are equally likely to occur and the flow can exhibit occasional and irregular ¡°reversals?from one to the other without a change in magnitude). It is usually referred to in the literature as ¡°wind of turbulence?or ¡°flywheel? The present article provides insights into the possible origin of such dynamics and related patterning behavior (supported by ¡°ad hoc?novel numerical simulations carried out for and ) together with a short exposition of existing theories, also illustrating open points and future directions of research.