Propagation of air fingers into an elastorigid Y-bifurcation
Propagation of air fingers into an elastorigid Y-bifurcation
复制标题
DOI：
10.1103/physrevfluids.8.094001
复制
发表时间：
2023-09
影响因子：
2.7
通讯作者：
Haolin Li;A. Juel;F. Box;D. Pihler-Puzović
中科院分区：
文献类型：
--
作者：
Haolin Li;A. Juel;F. Box;D. Pihler-Puzović
我们实验研究了通过弹性，充满液体的Hele-Shaw通道作为气道重新开放的台式模型的Y-分叉的空气指的传播。利用由弹性上边界提供的通道顺应性，我们可以施加塌陷的通道配置，我们以恒定的体积流速将空气注入其中。我们通常观察到稳定的手指传播的主通道，这是失去了前面的Y-分叉，但随后恢复的女儿通道。在低水平的初始崩溃，稳定的手指形状和气泡压力的子通道映射到那些在主通道。然而，在弹性片几乎接触通道的底部边界的较高水平的初始塌陷处，主通道中的实验上不可区分的指状物可以导致子通道重新打开的多个状态。稳定的传播恢复在女儿通道的下游距离也有很大的变化与注射流量和初始崩溃，因为在机械调节指传播的过渡。我们发现，这种恢复的特征时间和长度尺度是最大的制度，其中粘性和表面张力占主导地位的手指传播，他们减少到一个恒定的高原在弹性力取代粘性力的限制。我们的研究结果表明，实际的网络不太可能包括足够长的通道，以稳定状态的传播之间的分叉恢复。
We study experimentally the propagation of an air finger through the Y-bifurcation of an elastic, liquid-filled Hele-Shaw channel as a benchtop model of airway reopening. With channel compliance provided by an elastic upper boundary, we can impose collapsed channel configurations into which we inject air with constant volumetric flow rate. We typically observe steady finger propagation in the main channel, which is lost ahead of the Y-bifurcation but subsequently recovered in the daughter channels. At low levels of initial collapse, steady finger shapes and bubble pressure in the daughter channels map onto those in the main channel. However, at higher levels of initial collapse where the elastic sheet almost touches the bottom boundary of the channel, experimentally indistinguishable fingers in the main channel can lead to multiple states of reopening of the daughter channels. The downstream distance at which steady propagation is recovered in the daughter channels also varies considerably with injection flow rate and initial collapse because of a transition in the mechanics regulating finger propagation. We find that the characteristic time and length scales of this recovery are largest in the regime where viscous and surface tension forces dominate finger propagation and that they decrease towards a constant plateau in the limit where elastic forces supersede viscous forces. Our findings suggest that practical networks are unlikely to comprise long-enough channels for steady-state propagation to be recovered between bifurcations.