Bourgoin Mickaël, Ouellette Nicholas T, Xu Haitao, Berg Jacob, Bodenschatz Eberhard
Laboratoire des Ecoulements Géophysiques et Industriels-CNRS (Unité Mixte de Recherche 5519), Boite Postale 53-38041, Grenoble Cedex 9, France.
Science. 2006 Feb 10;311(5762):835-8. doi: 10.1126/science.1121726.
Mixing and transport in turbulent flows-which have strong local concentration fluctuations-are essential in many natural and industrial systems including reactions in chemical mixers, combustion in engines and burners, droplet formation in warm clouds, and biological odor detection and chemotaxis. Local concentration fluctuations, in turn, are intimately tied to the problem of the separation of pairs of fluid elements. We have measured this separation rate in an intensely turbulent laboratory flow and have found, in quantitative agreement with the seminal predictions of Batchelor, that the initial separation of the pair plays an important role in the subsequent spreading of the fluid elements. These results have surprising consequences for the decay of concentration fluctuations and have applications to biological and chemical systems.
在具有强烈局部浓度波动的湍流中的混合与输运，在许多自然和工业系统中至关重要，这些系统包括化学混合器中的反应、发动机和燃烧器中的燃烧、暖云中的液滴形成，以及生物气味检测和趋化作用。反过来，局部浓度波动又与流体元素对的分离问题紧密相关。我们在一个高度湍流的实验室流场中测量了这种分离速率，并且发现，与巴彻勒的开创性预测在定量上一致，即流体元素对的初始分离在随后流体元素的扩散中起着重要作用。这些结果对于浓度波动的衰减有着惊人的影响，并且在生物和化学系统中有应用。
