论文标题
液滴动力学和湍流级联的相互作用
The interaction of droplet dynamics and turbulence cascade
论文作者
论文摘要
在Kolmogorov-Hinze框架中描述了湍流中液滴碎片的动力学。然而，当阶段和聚结之间的强烈相互作用变得相关时，缺乏较高浓度的定量理论，这在大多数流中很常见。在这里，我们通过对高雷诺数在湍流中的液滴动力学进行完全耦合的数值研究来解决此问题。通过实验目前无法访问的时空频谱统计数据，我们证明了该过程的特征尺度，即Hinze量表，可以精确地确定为毛细管净能量交换为零的量表。大于该量表的液滴优先破坏流量的吸收能量。相反，较小的液滴经历了快速的振荡，并倾向于合并到流动的能量。此外，我们将液滴大小分布与湍流耗散的概率分布联系起来。这表明碎裂过程中的关键是能量的局部通量，它在大尺度上占主导地位，证明其位置。
The dynamics of droplet fragmentation in turbulence is described in the Kolmogorov-Hinze framework. Yet, a quantitative theory is lacking at higher concentrations when strong interactions between the phases and coalescence become relevant, which is common in most flows. Here, we address this issue through a fully-coupled numerical study of the droplet dynamics in a turbulent flow at high Reynolds number. By means of time-space spectral statistics, not currently accessible to experiments, we demonstrate that the characteristic scale of the process, the Hinze scale, can be precisely identified as the scale at which the net energy exchange due to capillarity is zero. Droplets larger than this scale preferentially break up absorbing energy from the flow; smaller droplets, instead, undergo rapid oscillations and tend to coalesce releasing energy to the flow. Further, we link the droplet-size-distribution with the probability distribution of the turbulent dissipation. This shows that key in the fragmentation process is the local flux of energy which dominates the process at large scales, vindicating its locality.
