Dynamics of front propagation in a compliant channel
Dynamics of front propagation in a compliant channel
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顺应通道中前向传播的动力学
DOI：
10.1017/jfm.2019.1037
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发表时间：
2020
影响因子：
3.7
通讯作者：
Cuttle C
中科院分区：
文献类型：
--
作者：
Cuttle C
前传播系统提供了界面不稳定性和图案形成的一些最基本的物理例子。然而，它们的非线性动力学很少得到解决。在这里，我们提出了一个实验研究的空气取代粘性流体在一个塌陷的，顺从的通道-一个模型的肺气道重开。空气以恒定的流量从充满液体的一端注入，塌陷的通道导致一个重新打开的手指的传播。根据施加的流速，我们观察到各种各样的指尖形态，这些形态随着手指的传播而持续发生或短暂进化。持久的手指是稳定的，因为它们在大约恒定的气泡压力下传播。我们发现它们的压力作为气泡速度的函数沿两条不相连的线单调增加。尽管与高气泡速度相关的管道显示出最小的压力值，但低速管道支持手指传播到最小的流量。我们提出的证据表明，低速和高速手指分别由粘性和弹性力主导。我们还发现，在没有观察到稳定的手指传播的情况下，将两条压力线分开的气泡速度范围。相反，复杂的瞬态动力学导致长期选择稳定的手指取决于初始条件。这些手指的早期瞬态演化的特征是气泡压力的增加和气泡速度的降低。我们假设存在一种弱不稳定的、稳定的模式，它协调了手指向低速或高速传播模式的短暂进化。
Front-propagating systems provide some of the most fundamental physical examples of interfacial instability and pattern formation. However, their nonlinear dynamics is rarely addressed. Here, we present an experimental study of air displacing a viscous fluid within a collapsed, compliant channel – a model for pulmonary airway reopening. Air injected at a constant flow rate from one end of the liquid-filled, collapsed channel results in the propagation of a reopening finger. Depending on the imposed flow rate, we observe a wide variety of finger-tip morphologies, which occur persistently or evolve transiently as the finger propagates. Persistent fingers are stable in the sense that they propagate with approximately constant bubble pressure. We find that their pressure increases monotonically as a function of bubble speed along two disconnected lines. Although the line associated with higher bubble speed exhibits a minimum pressure value, the low-speed line supports finger propagation down to the smallest flow rates investigated. We present evidence that the lower and higher-speed fingers are dominated by viscous and elastic forces, respectively. We also find a range of bubble speeds separating the two pressure lines where no stable finger propagation is observed. Instead, complex transient dynamics leads to the long-term selection of stable fingers depending on initial conditions. The early transient evolution of these fingers is characterised by an increase in bubble pressure alongside a reduction in bubble speed. We hypothesise the existence of a weakly unstable, steady mode, which orchestrates the transient evolution of the finger towards either low- or high-speed modes of propagation.
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DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
A. Heap;A. Juel
通讯作者：
A. Juel
DOI：
10.1016/s0378-4371(98)00345-8
发表时间：
1998-11-15
影响因子：
3.3
作者：
Golding, I;Kozlovsky, Y;Ben-Jacob, E
通讯作者：
Ben-Jacob, E
影响因子：
3.7
作者：
MCEWAN, AD;TAYLOR, GI
通讯作者：
TAYLOR, GI
影响因子：
8.6
作者：
Pihler-Puzovic, D.;Illien, P.;Juel, A.
通讯作者：
Juel, A.
塌陷弹刚性通道的重新打开模式
影响因子：
3.7
作者：
Lucie Ducloué;A. Hazel;A. Thompson;A. Juel
通讯作者：
A. Juel