Diffusion and spatial correlations in suspensions of swimming particles
Diffusion and spatial correlations in suspensions of swimming particles
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DOI：
10.1103/physrevlett.100.248101
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发表时间：
2008-06-20
影响因子：
8.6
通讯作者：
Graham, Michael D.
中科院分区：
文献类型：
--
作者：
Underhill, Patrick T.;Hernandez-Ortiz, Juan P.;Graham, Michael D.
游动的微生物群体产生流体运动，导致示踪粒子的扩散显著增强。使用模拟的悬浮液中的游泳粒子在一个周期性的域，我们捕捉到这种效果，并表明，它定性地取决于游泳的模式：游泳者“推”从后面由他们的鞭毛显示更大的增强比游泳者“拉”从前面。这种差异表现为被动示踪剂的扩散率和速度相关长度与周期域的大小的增加，这只发生在推杆。一个由平均场理论支持的物理论点揭示了这些效应的起源。
Populations of swimming micro-organisms produce fluid motions that lead to dramatically enhanced diffusion of tracer particles. Using simulations of suspensions of swimming particles in a periodic domain, we capture this effect and show that it depends qualitatively on the mode of swimming: swimmers "pushed" from behind by their flagella show greater enhancement than swimmers that are "pulled" from the front. The difference is manifested by an increase, that only occurs for pushers, of the diffusivity of passive tracers and the velocity correlation length with the size of the periodic domain. A physical argument supported by a mean field theory sheds light on the origin of these effects.