均匀剪切流中粒子无规行走的分子动力学模拟研究  

Molecular Dynamics Simulation of Random Walking Curves in Uniform Shear Flow

作　　者：赵浩焜 刘文斌 张劲柏[2] ZHAO Hao-kun;LIU Wen-bin;ZHANG Jin-bai(School of Aeronautic Science and Engineering,Beihang University,Beijng 100191,China;School of Aeronautic Science and Engineering,Beihang University,Beijng 100191,China;National Laboratory of Computational Fluid Dynamics,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学航空科学与工程学院,北京100191 [2]北京航空航天大学国家计算流体力学重点实验室,北京100191

出　　处：《佳木斯大学学报（自然科学版）》2018年第5期795-798,共4页Journal of Jiamusi University：Natural Science Edition

摘　　要：应用分子动力学模拟方法模拟了均匀剪切流,计算出不同均匀剪切流无规行走位移曲线,计算无规行走拟合曲线斜率。计算结果表明,在相同时间条件下,速度梯度越大,x轴方向无规行走曲线斜率增大,y轴z轴两个方向的无规行走曲线斜率越小。而同一剪切率下的y轴无规行走曲线与z轴无规行走曲线斜率的差别不大。在x轴方向分子无规行走位移的方均值与时间t的三次方成正比;在y轴、z轴方向分子无规行走的方均值与时间t成正比,分子扩散系数随着速度梯度增加而呈线性减小。Molecular dynamics simulation method was used to simulate the high shear rate Couette flow, calculate the random walk displacement curve of different shear rate Couette flow, and calculate the slope of fitting curve of random walk. The calculation results show that under the same time conditions, the greater the velocity gradient, the greater the slope of the random walk curve on the x-axis and the smaller the slope of the random walk curve on the z-axis of the y-axis. However, the difference between the random walk curve of the y-axis and the random walk curve of the z-axis under the same shear rate is not significant. The square mean of the molecular random walk displacement in the x-axis direction is proportional to the third power of time t; the square mean of the molecular random walk in the y-axis and z-axis directions is proportional to the time t, and the molecular diffusion coefficient increases with the velocity gradient linearly reduced.

关 键 词：分子动力学 COUETTE流 无规行走曲线 分子热运动 修正的周期性边界条件 

分 类 号：O365[理学—流体力学]