Granular gases are fascinating non-equilibrium systems with interesting features such as spontaneous clustering and non-Gaussian velocity distributions. Mixtures of different components represent a much more natural composition than monodisperse ensembles but attracted comparably little attention so far. We present the observation and characterization of a mixture of rod-like particles with different sizes and masses in a drop tower experiment. Kinetic energy decay rates during granular cooling and collision rates were determined and Haff’s law for homogeneous granular cooling was confirmed. Thereby, energy equipartition between the mixture components and between individual degrees of freedom is violated. Heavier particles keep a slightly higher average kinetic energy than lighter ones. Experimental results are supported by numerical simulations.

颗粒气体是令人着迷的非平衡系统，具有自发聚集和非高斯速度分布等有趣特征。不同成分的混合物代表了比单分散整体更自然的组成，但迄今为止引起的关注相对较少。我们展示了在落塔实验中对不同尺寸和质量的棒状颗粒混合物的观察和表征。测定了颗粒冷却过程中的动能衰减率和碰撞率，并确认了均匀颗粒冷却的哈夫定律。因此，混合物成分之间以及各个自由度之间的能量均等分配被破坏。较重的粒子比较轻的粒子保持稍高的平均动能。实验结果得到数值模拟的支持。