A set of experiments on avalanches—each one with a single particle size (monodisperse)—is presented. Experiments were performed with different flume lengths, inclinations, and roughness, for different avalanching masses and particle sizes. A transition from an inertial behavior to a frictional dominated one is observed at a particle size of 1 mm, in all cases. Taking into account the energy dissipated during each step of the avalanching process, we inferred a scaling function that allowed us to collapse all experimental data into a single curve. The transition from an inertial to a frictional dominated regime is explained in terms of the increasing number of particles per unit mass with decreasing particle size, for which the external shear activates a growing number of internal degrees of freedom in which the energy is dissipated. Molecular dynamic numerical simulations showed consistency with the suggested hypothesis of higher dissipated power for larger number of avalanching particles (smaller grain size).

中文翻译：

---

重力驱动的单分散雪崩：惯性主导到摩擦主导的流动

展示了一组关于雪崩的实验——每个实验都有一个单一的粒径（单分散）。针对不同的雪崩质量和粒度，使用不同的水槽长度、倾斜度和粗糙度进行了实验。在所有情况下，当粒径为 1 mm 时，观察到从惯性行为到摩擦主导行为的转变。考虑到雪崩过程中每一步耗散的能量，我们推断出一个缩放函数，使我们能够将所有实验数据折叠成一条曲线。从惯性到摩擦主导状态的转变可以通过每单位质量的粒子数量随着粒度的减小而增加来解释，为此，外部剪切激活了越来越多的内部自由度，其中能量耗散。