Wall-induced translation of a rotating particle in a shear-thinning fluid
Wall-induced translation of a rotating particle in a shear-thinning fluid
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DOI：
10.1017/jfm.2021.775
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发表时间：
2021-09-21
影响因子：
3.7
通讯作者：
Pak, On Shun
中科院分区：
文献类型：
--
作者：
Chen, Ye;Demir, Ebru;Pak, On Shun
颗粒-壁相互作用具有广泛的生物学和技术应用。特别是，一些人造微型游泳器利用其靠近墙壁的平移-旋转耦合来产生定向推进力。这些微型游泳器在复杂生物流体中的新兴生物医学应用引发了人们对非牛顿流变学对其推进力的影响的疑问。在这项工作中，我们报告了剪切稀化流变学（生物流体普遍存在的非牛顿行为）对壁附近粒子的平移-旋转耦合的一些有趣的影响。这里揭示的一个特别有趣的特征是，壁引起的旋转平移可能发生在与在固体基底上滚动的物体直观预期相反的方向上。我们阐明了潜在的物理机制，并讨论了其对微型机器设计和复杂流体中壁附近细菌运动的影响。
Particle-wall interactions have broad biological and technological applications. In particular, some artificial microswimmers capitalize on their translation-rotation coupling near a wall to generate directed propulsion. Emerging biomedical applications of these microswimmers in complex biological fluids prompt questions on the impact of non-Newtonian rheology on their propulsion. In this work, we report some intriguing effects of shear-thinning rheology, a ubiquitous non-Newtonian behaviour of biological fluids, on the translation-rotation coupling of a particle near a wall. One particularly interesting feature revealed here is that the wall-induced translation by rotation can occur in a direction opposite to what might be intuitively expected for an object rolling on a solid substrate. We elucidate the underlying physical mechanism and discuss its implications on the design of micromachines and bacterial motion near walls in complex fluids.