Li Zhifeng, Zeng Zhikun, Xing Yi, Li Jindong, Zheng Jie, Mao Qinghao, Zhang Jie, Hou Meiying, Wang Yujie
School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.
Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China.
Sci Adv. 2021 Feb 17;7(8). doi: 10.1126/sciadv.abe8737. Print 2021 Feb.
Granular mixtures with size difference can segregate upon shaking or shear. However, the quantitative study of this process remains difficult because it can be influenced by many mechanisms. Conflicting results on similar experimental systems are frequently obtained when the experimental conditions are not well controlled, which is mainly due to the fact that many mechanisms can be at work simultaneously. Moreover, it is often that macroscopic or empirical measures, which lack microscopic physical bases, are used to explain the experimental findings and therefore cannot provide an accurate and complete depiction of the overall process. Here, we carry out a detailed and systematic microscopic structure and dynamics study of a cyclically sheared granular system with rigorously controlled experimental conditions. We find that both convection and arching effect play important roles in the segregation process in our system, and we can quantitatively identify their respective contributions.
粒径不同的颗粒混合物在振动或剪切作用下会发生分离。然而，由于该过程会受到多种机制的影响，对其进行定量研究仍然困难重重。当实验条件控制不佳时，在相似的实验系统中经常会得到相互矛盾的结果，这主要是因为许多机制可能同时起作用。此外，人们常常使用缺乏微观物理基础的宏观或经验性方法来解释实验结果，因此无法对整个过程进行准确而完整的描述。在此，我们在严格控制实验条件的情况下，对一个周期性剪切颗粒系统进行了详细而系统的微观结构和动力学研究。我们发现，对流和拱效应在我们的系统分离过程中都起着重要作用，并且我们能够定量确定它们各自的贡献。
