Tegzes P, Vicsek T, Schiffer P
Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 May;67(5 Pt 1):051303. doi: 10.1103/PhysRevE.67.051303. Epub 2003 May 14.
A detailed characterization of avalanche dynamics of wet granular media in a rotating drum apparatus is presented. The results confirm the existence of the three wetness regimes observed previously: the granular, the correlated, and the viscoplastic regime. These regimes show qualitatively different dynamic behaviors that are reflected in all the investigated quantities. We discuss the effect of interstitial liquid on the characteristic angles of the material and on the avalanche size distribution. These data also reveal logarithmic aging and allow us to map out the phase diagram of the dynamic behavior as a function of liquid content and flow rate. Via quantitative measurements of the flow velocity and the granular flux during avalanches, we characterize avalanche types unique to wet media. We also explore the details of viscoplastic flow (observed at the highest liquid contents) in which there are lasting contacts during flow, leading to coherence across the entire sample. This coherence leads to a velocity independent flow depth at high rotation rates and robust pattern formation in the granular surface.
本文详细描述了旋转鼓装置中湿颗粒介质的雪崩动力学。结果证实了先前观察到的三种湿度状态的存在：颗粒态、关联态和粘塑性态。这些状态表现出定性不同的动态行为，这在所有研究的量中都有体现。我们讨论了间隙液体对材料特征角和雪崩尺寸分布的影响。这些数据还揭示了对数老化，并使我们能够绘制出作为液体含量和流速函数的动态行为相图。通过对雪崩过程中流速和颗粒通量的定量测量，我们表征了湿介质特有的雪崩类型。我们还探索了粘塑性流动（在最高液体含量下观察到）的细节，其中流动过程中存在持久接触，导致整个样品的连贯性。这种连贯性导致在高转速下流动深度与速度无关，并在颗粒表面形成稳健的图案。
