Liaw S-Y, Chung F F, Liaw S-S
Department of Physics, National Chung-Hsing University, Taichung, Taiwan.
Eur Phys J E Soft Matter. 2011 Jun;34(6):59. doi: 10.1140/epje/i2011-11059-x. Epub 2011 Jun 13.
We experimentally investigate the segregation of a binary mixture of spherical beads confined between two horizontal vertically vibrating plates. The two kinds of beads are of equal diameter and mass but have different restitution coefficients. Segregation occurs in particular ranges of vibration amplitude and frequency. We find that the collisions between beads at an angle to the horizontal plane induce an effective horizontal repulsive force. When one or both bead types bounce up and down in synchronization, the effective repulsive force between the two types of beads is likely to be larger than that found within a single bead type, resulting in the mixture segregating. Non-horizontal collisions also play a role in stabilizing the segregation state by transferring the horizontal kinetic energy back into vertical motion.
我们通过实验研究了限制在两个水平垂直振动平板之间的球形珠子二元混合物的分离现象。两种珠子直径和质量相等，但恢复系数不同。分离发生在特定的振动幅度和频率范围内。我们发现珠子与水平面成一定角度的碰撞会产生有效的水平排斥力。当一种或两种珠子同步上下弹跳时，两种珠子之间的有效排斥力可能大于单一珠子类型内的排斥力，从而导致混合物分离。非水平碰撞还通过将水平动能转化回垂直运动，在稳定分离状态方面发挥作用。
