Heterogeneous flow inside threads of low viscosity fluids leads to anomalous long filament lifetimes
Heterogeneous flow inside threads of low viscosity fluids leads to anomalous long filament lifetimes
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DOI：
10.1038/s41598-019-43590-z
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发表时间：
2019-05
影响因子：
4.6
通讯作者：
Steffen M. Recktenwald;S. Haward;A. Shen;N. Willenbacher
中科院分区：
文献类型：
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作者：
Steffen M. Recktenwald;S. Haward;A. Shen;N. Willenbacher
流体丝的形成和分裂在自然界和技术中是普遍的，其中通常观察到流体丝的高延展性和延长的丝寿命是流体粘弹性的结果。相比之下，像水这样的低粘度牛顿流体的线会很快破裂。在这里，我们证明了一个独特的带状模型表面活性剂溶液，粘度接近水和没有可测量的弹性，导致极长的长丝寿命和形成显着长的线程的细丝变薄过程中的不稳定性。在平面延伸以及剪切的补充测量表明，这种流动的不稳定性的特点是由多值应力，产生超过临界应变率，无论流动的运动学。我们的工作报告的第一次观察到这种现象在拉伸变形，并提供了一个统一的观点在复杂的流场的不稳定性。
Formation and breakup of fluid threads is pervasive in nature and technology, where high extensibility of fluid filaments and extended filament lifetimes are commonly observed as a consequence of fluid viscoelasticity. In contrast, threads of low viscous Newtonian fluids like water rupture quickly. Here, we demonstrate that a unique banding instability during filament thinning of model surfactant solutions, with a viscosity close to water and no measurable elasticity, leads to extremely long filament lifetimes and to the formation of remarkably long threads. Complementary measurements in planar extension as well as in shear reveal that this flow instability is characterized by a multivalued stress, arising beyond a critical strain rate, irrespective of flow kinematics. Our work reports the first observation of such phenomena during extensional deformation and provides a unifying view on instabilities in complex flow fields.