纳米柱绕流的分子动力学模拟分析  

Molecular Dynamics Simulation Study on Cylinder Obstructed Fluid Flow

作　　者：高阳[1] 洪俊[1] 

机构地区：[1]东南大学工程力学系,南京210096

出　　处：《力学季刊》2010年第2期145-150,共6页Chinese Quarterly of Mechanics

基　　金：国家重点基础研究发展计划(No.2009CB623202);江苏省自然科学基金(BK2009259)

摘　　要：采用分子动力学方法,对不同雷诺数的纳米柱绕流问题进行模拟。统计及对比结果表明,在微观尺度下的纳米圆柱绕流的流场与宏观的圆柱绕流类似,但又具有自己的特点。雷诺数为16.2时,圆柱后会持续的周期性产生漩涡并脱落,类似宏观现象中的卡门涡街;而雷诺数为5.4时的圆柱后面没有出现漩涡。流场中圆柱表面存在速度滑移,说明无滑移不是产生漩涡的必要条件。圆柱前后会分别形成高压区和低压区,压强差的大小与来流速度有关。流场中存在顺压强梯度和逆压强梯度,顺压强梯度使圆柱上下两边区域流速超过来流速度,而逆压强梯度则会减小流速甚至使流场中出现回流。流场中密度最小处分布在圆柱右上和右下附近而不是圆柱的正后方。Molecular dynamics simulations were carried out to study the fluid flow pass a circular cylinder at different Reynolds number at microscopic level.The results show that the behavior of the flow is common to that at macroscopic level,but not identical.When Reynolds number is 16.2,the alternate eddy formation and shedding are repeated and the phenomenon is common to Karman Vortex Street.But when Reynolds number is 5.4,no eddy occurs.The velocity slip exists around the cylinder when the eddy occurs,which identify that non-slip is not necessary to the formation of eddy.The pressure of the fluid in the upstream region is greater than that in the downstream region and the grad is sensitive to the velocity of flow.The minimum value of density didn＇t occur in the back of the cylinder but upper and lower of that region.

关 键 词：分子动力学 圆柱绕流 漩涡 

分 类 号：O357[理学—流体力学]