Panaitescu Andreea, Kudrolli Arshad
Department of Physics, Clark University, Worcester, Massachusetts 01610, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Jun;81(6 Pt 1):060301. doi: 10.1103/PhysRevE.81.060301. Epub 2010 Jun 8.
We measure the two-point density correlations and Voronoi cell distributions of cyclically sheared granular spheres obtained with a fluorescence technique and compare them with random packing of frictionless spheres. We find that the radial distribution function g(r) is captured by the Percus-Yevick equation for initial volume fraction ϕ=0.59. However, small but systematic deviations are observed because of the splitting of the second peak as ϕ is increased toward random close packing. The distribution of the Voronoi free volumes deviates from postulated Γ distributions, and the orientational order metric Q6 shows local order but no long range order. Overall, these measures show significant similarity of random packing of granular and frictionless spheres, but some systematic differences as well.
我们用荧光技术测量了循环剪切颗粒球的两点密度相关性和Voronoi胞分布，并将其与无摩擦球的随机堆积进行比较。我们发现，对于初始体积分数ϕ = 0.59，径向分布函数g(r)由Percus-Yevick方程描述。然而，随着ϕ向随机密堆积增加，由于第二峰的分裂，观察到了微小但系统的偏差。Voronoi自由体积的分布偏离了假定的Γ分布，取向序度量Q6显示出局部有序但无长程有序。总体而言，这些测量结果表明颗粒球和无摩擦球的随机堆积有显著的相似性，但也存在一些系统差异。
