Flow topology and scalar mixing in spatially heterogeneous flow fields
Flow topology and scalar mixing in spatially heterogeneous flow fields
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DOI：
10.1029/2012gl051302
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发表时间：
2012-04-26
影响因子：
5.2
通讯作者：
Nowak, Wolfgang
中科院分区：
文献类型：
--
作者：
de Barros, Felipe P. J.;Dentz, Marco;Nowak, Wolfgang
标量混合在地球物理流中的输运中起着重要作用，因为它控制稀释，并且是许多化学反应的主要驱动力。在这里，我们研究了局部尺度流动机制，导致增强标量混合，以及它们如何影响全球混合行为。混合量化的标量分布的熵。它示出的熵的演变是直接链接到的Okubo-Weiss参数θ方面的流拓扑。主导的剪切和拉伸变形（θ> 0）导致局部混合强度的强烈增加，而主导的涡度（θ < 0）只有很小的影响。这使得可以通过绘制Theta（x）的空间分布来描绘标量混合潜力增加的区域，并将全球标量混合与区域平均有效Okubo-Weiss测量联系起来。引文：de Barros，F. P.J.，M. Dentz，J. Koch，and W. Nowak（2012），空间非均匀流场中的流拓扑和标量混合，Geophys。保留信函：39，L08404，doi：10.1029/2012GL051302。
Scalar mixing plays a significant role for transport in geophysical flows because it controls dilution and is a main driver for many chemical reactions. Here we study the local scale flow mechanisms that lead to enhanced scalar mixing, and how they impact on the global mixing behavior. Mixing is quantified in terms of the entropy of the scalar distribution. It is shown that the evolution of entropy is directly linked to the flow topology in terms of the Okubo-Weiss parameter Theta. Dominant shear and stretching deformation (Theta > 0) leads to a strong increase of local mixing strength, while dominant vorticity (Theta < 0) has only a minor impact. This allows to delineate regions of increased scalar mixing potential by mapping out the spatial distribution of Theta(x), and to relate global scalar mixing to an areal averaged effective Okubo-Weiss measure. Citation: de Barros, F. P. J., M. Dentz, J. Koch, and W. Nowak (2012), Flow topology and scalar mixing in spatially heterogeneous flow fields, Geophys. Res. Lett., 39, L08404, doi:10.1029/2012GL051302.