Statistical analysis of global wind dynamics in vigorous Rayleigh-Bénard convection.
Statistical analysis of global wind dynamics in vigorous Rayleigh-Bénard convection.
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DOI：
10.1103/physreve.84.026309
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
K. Petschel;M. Wilczek;M. Breuer;R. Friedrich;U. Hansen
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文献类型：
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作者：
K. Petschel;M. Wilczek;M. Breuer;R. Friedrich;U. Hansen
热对流的实验和数值研究表明，足够强烈的对流表现出沿小尺度热边界层不稳定的大尺度热风分量。这些流动的一个特征是在大尺度环流方向上表现为不规则反转的间歇性行为。为了更好地理解和描述反流现象，人们进行了几次尝试，但到目前为止，大多数这些模型都是基于对少数点测量的统计分析或基于简化的理论假设。通过对湍流二维Rayleigh-Bénard对流数值模拟获得的长期数据集(>；5×10(5)周转时间τ(T)=d/u(Rms))的分析，我们可以更全面地了解时空流动行为。通过对流动特征空间模式的全局统计分析，在状态子空间中提取了主导大尺度模式的稳定性信息和反转路径信息。我们研究了不同大尺度空间模跨越的二维状态子空间的概率密度函数和漂移矢量场。这也提供了有关主模共存的信息。
Experimental and numerical studies of thermal convection have shown that sufficiently vigorous convective flows exhibit a large-scale thermal wind component sweeping along small-scale thermal boundary layer instabilities. A characteristic feature of these flows is an intermittent behavior in the form of irregular reversals in the orientation of the large-scale circulation. There have been several attempts toward a better understanding and description of the phenomenon of flow reversals, but so far most of these models are based on a statistical analysis of few-point measurements or on simplified theoretical assumptions. The analysis of long-term data sets (>5×10(5) turnover times τ(t)=d/u(rms)) obtained by numerical simulations of turbulent two-dimensional Rayleigh-Bénard convection allows us to get a more comprehensive view of the spatio-temporal flow behavior. By means of a global statistical analysis of the characteristic spatial modes of the flow we extract information about the stability of dominant large-scale modes as well as the reversal paths in state subspace. We examine probability density functions and drift vector fields of two-dimensional state subspaces spanned by different large-scale spatial modes. This also provides information about the coexistence of dominant modes.