论文标题
摩擦颗粒液中的入侵者动力学：一项分子动力学研究
Intruder Dynamics in a Frictional Granular Fluid: A Molecular Dynamics Study
论文作者
论文摘要
我们研究了在三个维度上通过流化的颗粒介质移动的入侵者的动力学（$ d = 3 $）。入侵者和晶粒具有自由的转化和旋转程度。能量驱动机制是所有颗粒对之间的固体摩擦。通过随机扰动晶粒的线性和角速度，我们即使在相当高的密度下保持颗粒系统的流动。我们将恒定的外部力量$ f $应用于入侵者，并在谷物的质量中心框架中获得其稳态速度$ v_s $。 $ f $ - $ v_s $关系在粒状物质的工业处理中引起了极大的兴趣，并且一直是大多数实验的主题。我们还获得了与反向粘度成正比的移动性，该函数是音量分数$ ϕ $的函数。这表明这在干扰体积分数上有所不同。对于低于干扰部分的$ ϕ $，我们发现小$ f $的$ v_s \ sim f $和$ v_s \ sim f^{1/2} $对于大$ f $。入侵者显示垂直于外力方向的平面中的扩散运动。
We study the dynamics of an intruder moving through a fluidized granular medium in three dimensions ($d=3$). The intruder and grains have both translational and rotational degrees of freedom. The energy-dissipation mechanism is solid friction between all pairs of particles. We keep the granular system fluidized even at rather high densities by randomly perturbing the linear and angular velocities of the grains. We apply a constant external force of magnitude $F$ to the intruder, and obtain its steady state velocity $V_s$ in the center-of-mass frame of the grains. The $F$-$V_s$ relation is of great interest in the industrial processing of granular matter, and has been the subject of most experiments on this problem. We also obtain the mobility, which is proportional to the inverse viscosity, as a function of the volume fraction $ϕ$. This is shown to diverge at the jamming volume fraction. For $ϕ$ below the jamming fraction, we find that $V_s \sim F$ for small $F$ and $V_s \sim F^{1/2}$ for large $F$. The intruder shows diffusive motion in the plane perpendicular to the direction of the external force.
