Collective nonlinear behavior of interacting polydisperse microbubble clusters
Collective nonlinear behavior of interacting polydisperse microbubble clusters
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DOI：
10.1016/j.ultsonch.2019.104708
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发表时间：
2019-11-01
影响因子：
8.4
通讯作者：
Kolios, Michael C.
中科院分区：
文献类型：
--
作者：
Haghi, H.;Sojahrood, A. J.;Kolios, Michael C.
声激发微泡(MBS)具有丰富的动力学特性，在化学和医学等领域具有广泛的应用前景。要充分挖掘MBS的应用潜力，需要对其复杂的动力学有很好的了解。提高对甲基溴振荡的理解可以进一步增强其在许多应用中的有效性，还可以发明新的应用。振荡的MBS已被证明会产生二次压力波，从而改变其附近MBS的动态。用修正的Keller-Miksis方程来解释气泡间的相互作用。通过数值求解在势流中耦合的二阶非线性微分方程组，计算了团簇内每个MB的振荡动力学。利用频响分析和分叉图跟踪了相互作用的MBS的动力学行为。我们首先研究了在广泛的声学和几何参数范围内，三个和四个MB的情况下气泡间相互作用的影响。观察到了紧急集体行为，这是由星团内最大MB的动态所主导的。团簇内较小的MBS的涌现动力学可以用建设性的和破坏性的气泡间相互作用来表征。在构造性相互作用中，较小MB的径向振荡与最大MB的径向振荡相匹配，且其振荡被放大。在破坏性相互作用中，较小气泡的振荡被抑制，以便它们的振荡与最大MB的振荡相匹配。此外，还给出了一个构造性相互作用的特例，其中占主导地位的MB(最大)可以迫使较小的MB进入倍周期和亚谐振荡。进一步研究了大MB团簇的集体行为，结果表明，最大的MB，即使是少量的，也可以迫使较小的MB进入倍周期和亚谐振荡。
Acoustically excited microbubbles (MBs) have shown to exhibit rich dynamics, enabling them to be employed in various applications ranging from chemistry to medicine. Exploiting the full potential of MBs for applications requires a good understanding of their complex dynamics. Improved understanding of MB oscillations can lead to further enhancement in optimizing their efficacy in many applications and also invent new ones. Oscillating MBs have been shown to generate secondary pressure waves that modify the dynamics of the MBs in their proximity. A modified Keller-Miksis equation is used to account for inter-bubble interactions. The oscillatory dynamics of each MB within clusters was computed by numerically solving the resulting system of coupled nonlinear second order differential equations in potential fluid flow. Frequency response analysis and bifurcation diagrams were employed to track the dynamics of interacting MBs. We start with investigating the effect of inter-bubble interactions for cases of three and four MBs over a wide range of acoustic and geometric parameters. Emergent collective behavior was observed which are dominated by the dynamics of the largest MB within the cluster. The emergent dynamics of smaller MBs within clusters can be characterized by constructive and destructive inter-bubble interactions. In constructive interactions, the radial oscillations of smaller MBs matched those of the largest MB and their oscillations are amplified. In destructive interactions, the oscillations of smaller bubbles are suppressed so that their oscillations match those of the largest MB. Furthermore, a special case of constructive interactions is presented where dominant MB (largest) can force smaller MBs into period doubling and subharmonic oscillations. The collective behavior is further investigated in large MB cluster and it is shown that largest MBs, even in small numbers can force smaller ones into period doubling and subharmonic oscillations.