Thermal fluctuations of hydrodynamic flows in nanochannels
Thermal fluctuations of hydrodynamic flows in nanochannels
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DOI：
10.1103/physreve.88.012106
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发表时间：
2013-07-08
影响因子：
2.4
通讯作者：
Bocquet, Lyderic
中科院分区：
文献类型：
--
作者：
Detcheverry, Francois;Bocquet, Lyderic
纳米级的流动会受到热波动的影响。在这项工作中，我们探索了限制在纳米尺寸通道内的流体的后果。首先，分子动力学模拟的基础上说明的现象。封闭流体的质心表现为随机的非马尔可夫运动，其扩散系数满足爱因斯坦关系，并可以进一步表征的波动关系。接下来，我们对热致流体运动进行了分析描述。我们计算的时间和空间相关的速度相关函数，并表征其依赖于纳米孔的形状，尺寸和表面的边界滑移。质量和电荷传输的实验影响进行了讨论两种情况。对于被限制在纳米孔内的颗粒，我们表明，流体波动运动的结果在增强的扩散。第二种情况涉及带电纳米孔，其中双层内的流体运动引起波动电流。我们计算对当前功率谱的相应贡献。
Flows at the nanoscale are subject to thermal fluctuations. In this work, we explore the consequences for a fluid confined within a channel of nanometric size. First, the phenomenon is illustrated on the basis of molecular dynamics simulations. The center of mass of the confined fluid is shown to perform a stochastic, non-Markovian motion, whose diffusion coefficient satisfies Einstein's relation, and which can be further characterized by the fluctuation relation. Next, we develop an analytical description of the thermally induced fluid motion. We compute the time- and space-dependent velocity correlation function, and characterize its dependence on the nanopore shape, size, and boundary slip at the surface. The experimental implications for mass and charge transports are discussed for two situations. For a particle confined within the nanopore, we show that the fluid fluctuating motion results in an enhanced diffusion. The second situation involves a charged nanopore in which fluid motion within the double layer induces a fluctuating electric current. We compute the corresponding contribution to the current power spectrum.