论文标题
围绕圆形纳米缸流动的分子动力学模拟
Molecular dynamics simulation of flow around a circular nano-cylinder
论文作者
论文摘要
在这项研究中，通过分子动力学模拟对圆形纳米缸围绕的尾流进行数值研究，以揭示微/纳米尺寸对尾流的影响。当雷诺数（RE）> 101有效地影响尾流时，发生气态发生。唤醒流的曲线数（ST）随着RE在低RE时的增加而增加，但在气穴出现后随着RE的稳定减少。升力力波动的主要频率可以高于速度波动的频率，当重新{\ geq} 127时，在布朗力的混乱波动背景中淹没了。为了考虑流体的内部尺寸效应，新引入的JZ数字定义为流体分子的平均自由路径λ与势能σ的平衡距离之间的比率。尾流的ST随JZ的增加而增加，直到当Jz {\ of Youts} 1.7时，它急剧下降到零。它表示流体的不连续性最终可以消除涡流的产生和脱落。同时，由于空化的强度，ST随着KN的速度减小。
In this study, the wake flow around a circular nano-cylinder is numerically investigated with molecular dynamics simulation to reveal the micro/nano size effect on the wake flow. The cavitation occurring when Reynolds number (Re) > 101 can effectively influence the wake flow. The Strouhal number (St) of the wake flow increases with the Re at low Re, but steadily decreases with the Re after the cavitation appears. The dominant frequency of the lift force fluctuation can be higher than that of the velocity fluctuation, and be drowned in the chaotic fluctuating background of the Brownian forces when Re {\geq} 127. Also because of the strong influence of the Brownian forces, no dominant frequency of the drag force fluctuation can be observed. The Jz number, which is defined as the ratio between the mean free path λ of the fluid molecules and the equilibrium distance of potential energy σ, is newly introduced in order to consider the internal size effect of fluid. The St of the wake flow increases with the Jz until it falls to zero sharply when Jz {\approx} 1.7. It denotes the discontinuity of the fluid can eventually eliminate the vortex generation and shedding. Meanwhile, the St decreases with the Kn because of the intensification of the cavitation.
