Disorder Suppresses Chaos in Viscoelastic Flows
Disorder Suppresses Chaos in Viscoelastic Flows
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DOI：
10.1103/physrevlett.124.164501
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发表时间：
2020-04-20
影响因子：
8.6
通讯作者：
Guasto, Jeffrey S.
中科院分区：
文献类型：
--
作者：
Walkama, Derek M.;Waisbord, Nicolas;Guasto, Jeffrey S.
在临界流动条件下，通过微结构几何形状的粘弹性流动从稳定过渡到时间依赖和混沌动力学。然而，几何紊乱对流动稳定性的影响是未知的。我们测量的粘弹性流动通过微流控柱阵列的时空速度波动的发病，具有控制的几何紊乱的变化。引入一个小的扰动到柱阵列（类似于10%的晶格常数）延迟的不稳定性的发作，以更高的流速，而更大的障碍（>= 25%）抑制过渡到混沌。我们发现，无序引入优先流动路径，促进剪切拉伸变形和局部减少聚合物拉伸，提高流动稳定性。
Viscoelastic flows through microstructured geometries transition from steady to time dependent and chaotic dynamics under critical flow conditions. However, the implications of geometric disorder for flow stability are unknown. We measure the onset of spatiotemporal velocity fluctuations for a viscoelastic flow through microfluidic pillar arrays, having controlled variations of geometric disorder. Introducing a small perturbation into the pillar array (similar to 10% of the lattice constant) delays the onset of the instability to higher flow speed, and yet larger disorders (>= 25%) suppress the transition to chaos. We show that disorder introduces preferential flow paths that promote shear over extensional deformation and enhance flow stability by locally reducing polymer stretching.