Wang Hong-qiang, Jin Guo-jun, Ma Yu-qiang
National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Sep;68(3 Pt 1):031301. doi: 10.1103/PhysRevE.68.031301. Epub 2003 Sep 3.
We study the unequal kinetic temperatures in two-dimensional binary granular mixtures heated by vertical vibrations under gravity by molecular dynamics simulations. By introducing several variable parameters describing particle and composition properties of mixtures, the coexistence of two different kinetic temperatures for the two components is exhibited. In dilute situations, our numerical results confirm the overall experimental measurements by Feitosa and Menon recently [Phys. Rev. Lett. 88, 198301 (2002)]. For example, the temperature ratio along the vertical direction is constant in the bulk of a system, and is insensitive to external driving or relative concentration of the two components, but mainly influenced by their masses. However, outside of the dilute situations, especially as the number density becomes high enough where the spatial and momentum correlations become salient, the ratio profiles show some different characteristics. Generally, the plateau shape along the vertical direction is broken, and instead, a saddlelike shape appears. Furthermore, the physical implications are discussed.
我们通过分子动力学模拟研究了在重力作用下由垂直振动加热的二维二元颗粒混合物中不等的动力学温度。通过引入几个描述混合物颗粒和组成特性的可变参数，展示了两种组分存在两种不同的动力学温度。在稀溶液情况下，我们的数值结果证实了费托萨和梅农最近的总体实验测量结果[《物理评论快报》88, 198301 (2002)]。例如，系统主体中沿垂直方向的温度比是恒定的，并且对外部驱动或两种组分的相对浓度不敏感，但主要受它们质量的影响。然而，在稀溶液情况之外，特别是当数密度变得足够高以至于空间和动量相关性变得显著时，比率分布显示出一些不同的特征。一般来说，沿垂直方向的平台形状被打破，取而代之的是出现鞍状形状。此外，还讨论了其物理意义。
