Sheared active fluids: Thickening, thinning, and vanishing viscosity
Sheared active fluids: Thickening, thinning, and vanishing viscosity
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DOI：
10.1103/physreve.81.051908
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发表时间：
2010-05-01
影响因子：
2.4
通讯作者：
Marchetti, M. Cristina
中科院分区：
文献类型：
--
作者：
Giomi, Luca;Liverpool, Tanniemola B.;Marchetti, M. Cristina
我们分析了活性极性颗粒悬浮液在剪切作用下的行为。在没有外力的情况下，已知定向有序的活性粒子会表现出向非均匀极化和自发流动状态的转变。这种转变是由悬浮液的液晶性引起的弹性应力与内部主动应力之间的相互作用造成的。在存在外部剪切的情况下，我们发现了极其丰富的现象，包括根据主动应力的性质和颗粒的流动排列特性而有效降低（增加）表观粘度，以及更奇特的行为，例如非单调应力-应变率关系和大型活动的屈服应力。
We analyze the behavior of a suspension of active polar particles under shear. In the absence of external forces, orientationally ordered active particles are known to exhibit a transition to a state of nonuniform polarization and spontaneous flow. Such a transition results from the interplay between elastic stresses, due to the liquid crystallinity of the suspension, and internal active stresses. In the presence of an external shear, we find an extremely rich variety of phenomena, including an effective reduction (increase) in the apparent viscosity depending on the nature of the active stresses and the flow-alignment property of the particles, as well as more exotic behaviors such as a nonmonotonic stress-strain-rate relation and yield stress for large activities.