Vortex-ring-induced stratified mixing
Vortex-ring-induced stratified mixing
复制标题
涡环诱导分层混合
DOI：
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发表时间：
2015
影响因子：
3.7
通讯作者：
S. Dalziel
中科院分区：
文献类型：
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作者：
J. Olsthoorn;S. Dalziel
有诱人的证据表明，一些机械驱动的分层流倾向于一个恒定的混合效率的状态。我们提供了对导致恒定混合效率的能量平衡的深入了解，并分离出负责的机制。所提出的工作表明了一个重要的混合效率制度，定期强制外部驱动的分层流。外部强制分层湍流混合的特征通常在于流内的相关涡流，这是主要的混合机制（Turner，J. Fluid Mech.，第173卷，1986年，第173页。431-471）。在这里，我们研究涡环诱导的混合，以表征单个涡诱导的混合。通过在具有尖锐界面的密度分层流体中产生一系列独立的涡环混合事件，我们确定了每个环的混合效率。经过一个初始的调整阶段，我们发现，每个涡环的混合效率是独立的理查森数。通过研究这里的混合机制，我们展示了一致的功能的体积限制，定期强制外部混合制度。
There is tantalizing evidence that some mechanically driven stratified flows tend towards a state of constant mixing efficiency. We provide insight into the energy balance leading to the constant mixing efficiency and isolate the responsible mechanism. The work presented demonstrates an important mixing efficiency regime for periodically forced externally driven stratified flows. Externally forced stratified turbulent mixing is often characterized by the associated eddies within the flow, which are the dominant mixing mechanism (Turner, J. Fluid Mech., vol. 173, 1986, pp. 431–471). Here, we study mixing induced by vortex rings in order to characterize the mixing induced by an individual eddy. By generating a long sequence of independent vortex-ring mixing events in a density-stratified fluid with a sharp interface, we determine the mixing efficiency of each ring. After an initial adjustment phase, we find that the mixing efficiency of each vortex ring is independent of the Richardson number. By studying the mixing mechanism here, we demonstrate consistent features of a volumetrically confined, periodically forced external mixing regime.