Keblinski P, Thomin J
Materials Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Jan;73(1 Pt 1):010502. doi: 10.1103/PhysRevE.73.010502. Epub 2006 Jan 27.
We use molecular dynamics simulations of a solid Brownian particle in an explicit solvent to analyze the velocity field generated by a stochastic motion of a particle. The simulation data demonstrate that the amplitude of the velocity field around a Brownian particle decays much faster than the velocity field around a particle moving with a constant velocity. However, the time-integrated response of the velocity field around a Brownian particle has exactly the same distance dependence as the velocity field around a particle moving with a constant velocity. This finding elucidates the validity of an assumption used in theoretical descriptions of Brownian particles dynamics in confined geometries and in colloids; namely, that viscous drag forces can be computed as if the particles move with constant velocities.
我们使用在显式溶剂中的固体布朗粒子的分子动力学模拟，来分析由粒子的随机运动产生的速度场。模拟数据表明，布朗粒子周围速度场的振幅衰减比匀速运动粒子周围的速度场快得多。然而，布朗粒子周围速度场的时间积分响应与匀速运动粒子周围的速度场具有完全相同的距离依赖性。这一发现阐明了在受限几何结构和胶体中布朗粒子动力学理论描述中使用的一个假设的有效性；即粘性阻力可以像粒子以恒定速度运动那样来计算。
