Hydrodynamic instabilities in miscible fluids
Hydrodynamic instabilities in miscible fluids
复制标题
混溶流体中的流体动力学不稳定性
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
L. Cipelletti
中科院分区：
文献类型：
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作者：
D. Truzzolillo;L. Cipelletti
从自然现象到地质尺度，再到工业和技术应用，混相流体中的流体动力学不稳定性无处不在，在这些应用中，它们是控制和促进低雷诺数混合的唯一途径，远远低于从层流到湍流的转变。对于不相容流体，其流体动力不稳定性的发生与其界面的物理性质直接相关。因此，这篇综述的重点是在各种强迫条件下，在混相流体之间的边界上驱动扰动增长的一般机制。在没有正规化机制的情况下，这些骚乱将无限期地滋长。对于不相容的流体，界面张力提供了这样一种调节机制，因为不断增长的扰动会产生新的界面，从而产生能量成本。然而，对于可混溶的流体，模拟有效表面张力的界面应力的存在是有争议的。然而，其他机制也可能是相关的，例如粘性耗散。我们将回顾控制最常见的流体动力不稳定性的稳定机制，重点介绍缺乏有效的界面张力在线性稳定性分析的数学公式中造成深层次概念问题的情况。最后，我们提供了一个简短的概述正在进行的研究，有效的，不平衡的界面张力之间的混相流体。
Hydrodynamic instabilities in miscible fluids are ubiquitous, from natural phenomena up to geological scales, to industrial and technological applications, where they represent the only way to control and promote mixing at low Reynolds numbers, well below the transition from laminar to turbulent flow. As for immiscible fluids, the onset of hydrodynamic instabilities in miscible fluids is directly related to the physics of their interfaces. The focus of this review is therefore on the general mechanisms driving the growth of disturbances at the boundary between miscible fluids, under a variety of forcing conditions. In the absence of a regularizing mechanism, these disturbances would grow indefinitely. For immiscible fluids, interfacial tension provides such a regularizing mechanism, because of the energy cost associated to the creation of new interface by a growing disturbance. For miscible fluids, however, the very existence of interfacial stresses that mimic an effective surface tension is debated. Other mechanisms, however, may also be relevant, such as viscous dissipation. We shall review the stabilizing mechanisms that control the most common hydrodynamic instabilities, highlighting those cases for which the lack of an effective interfacial tension poses deep conceptual problems in the mathematical formulation of a linear stability analysis. Finally, we provide a short overview on the ongoing research on the effective, out of equilibrium interfacial tension between miscible fluids.