Influence of the angle between the wind and the isothermal surfaces on the boundary layer structures in turbulent thermal convection.
Influence of the angle between the wind and the isothermal surfaces on the boundary layer structures in turbulent thermal convection.
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DOI：
10.1103/physreve.89.033014
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发表时间：
2014-03
期刊：
影响因子：
--
通讯作者：
O. Shishkina;S. Wagner;S. Horn
中科院分区：
文献类型：
--
作者：
O. Shishkina;S. Wagner;S. Horn
对于具有层流边界层的湍流热对流，我们导出了普朗特数Pr为无穷小和无穷小时热粘性边界层厚度比的渐近线，它是大尺度环流与等温加热或冷却表面之间夹角β的函数。为此目的，我们应用Falkner-Skan分析，这是一个推广的普朗特-Blasius一个非水平的自由流的粘性边界层上方的流动。基于我们对湍流Rayleigh-Bénard对流的直接数值模拟（DNS），Pr=0.1，1和10，中等瑞利数高达108，我们评估了β值，发现所有研究情况下的β值约为0.7π。我们对该β和所考虑的Pr的边界层厚度的理论预测与DNS结果很好地一致。
We derive the asymptotes for the ratio of the thermal to viscous boundary layer thicknesses for infinite and infinitesimal Prandtl numbers Pr as functions of the angle β between the large-scale circulation and an isothermal heated or cooled surface for the case of turbulent thermal convection with laminar-like boundary layers. For this purpose, we apply the Falkner-Skan ansatz, which is a generalization of the Prandtl-Blasius one to a nonhorizontal free-stream flow above the viscous boundary layer. Based on our direct numerical simulations (DNS) of turbulent Rayleigh-Bénard convection for Pr=0.1, 1, and 10 and moderate Rayleigh numbers up to 108 we evaluate the value of β that is found to be around 0.7π for all investigated cases. Our theoretical predictions for the boundary layer thicknesses for this β and the considered Pr are in good agreement with the DNS results.