Noirhomme M, Cazaubiel A, Falcon E, Fischer D, Garrabos Y, Lecoutre-Chabot C, Mawet S, Opsomer E, Palencia F, Pillitteri S, Vandewalle N
GRASP, CESAM Research Unit, Institut de Physique B5a, Sart Tilman, University of Liège, B-4000 Liège, Belgium.
Université de Paris, Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, F-75013 Paris, France.
Phys Rev Lett. 2021 Mar 26;126(12):128002. doi: 10.1103/PhysRevLett.126.128002.
We study experimentally the dynamical behavior of few large tracer particles placed in a quasi-2D granular "gas" made of many small beads in a low-gravity environment. Multiple inelastic collisions transfer momentum from the uniaxially driven gas to the tracers whose velocity distributions are studied through particle tracking. Analyzing these distributions for an increasing system density reveals that translational energy equipartition is reached at the onset of the gas-liquid granular transition corresponding to the emergence of local clusters. The dynamics of a few tracer particles thus appears as a simple and accurate tool to detect this transition. A model is proposed for describing accurately the formation of local heterogeneities.
我们通过实验研究了在低重力环境下，置于由许多小珠子构成的准二维颗粒“气体”中的少量大型示踪粒子的动力学行为。多次非弹性碰撞将动量从单轴驱动的气体传递到示踪粒子，通过粒子跟踪来研究示踪粒子的速度分布。分析随着系统密度增加的这些分布表明，在对应于局部团簇出现的气-液颗粒转变开始时，达到了平动能均分。因此，少量示踪粒子的动力学行为似乎是检测这种转变的一种简单而准确的工具。提出了一个模型来准确描述局部不均匀性的形成。
