Turbulent thermal convection in a closed domain: viscous boundary layer and mean flow effects
Turbulent thermal convection in a closed domain: viscous boundary layer and mean flow effects
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DOI：
10.1140/epjb/e2003-00264-6
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发表时间：
2003-09
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影响因子：
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通讯作者：
R. Verzicco
中科院分区：
文献类型：
--
作者：
R. Verzicco
本文采用Boussinesq近似下的Navier-Stokes方程直接数值模拟方法，分析了粘性边界层和平均流结构对细长圆柱形单胞内流动换热的影响。理想的流量产生抑制粘性边界层，并通过人为地强制执行流轴对称的目的是检查一些建议的解释Nusselt数依赖于瑞利数。新出现的图象表明，在这种细长几何形状中，粘性边界层的存在对Nuv. raration的斜率没有明显的影响，而平均流的转变很可能是Ra =2 x 109附近所观察到的斜率增加的原因。
In this paper the effects of viscous boundary layers and mean flow structures on the heat transfer of a flow in a slender cylindrical cell are analysed using the direct numerical simulation of the Navier-Stokes equations with the Boussinesq approximation. Ideal flows are produced by suppressing the viscous boundary layers and by artificially enforcing the flow axisymmetry with the aim of checking some proposed explanations for the Nusselt number dependence on the Rayleigh number. The emerging picture suggests that, in this slender geometry,the presence of the viscous boundary layers does not have appreciable impact on the slope of theNuvs.Rarelation while a transition of the mean flow is most likely the reason for the slope increase observed aroundRa=2 x 109.