Albert I, Tegzes P, Albert R, Sample J G, Barabási A, Vicsek T, Kahng B, Schiffer P
Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Sep;64(3 Pt 1):031307. doi: 10.1103/PhysRevE.64.031307. Epub 2001 Aug 30.
We study fluctuations in the drag force experienced by an object moving through a granular medium. The successive formation and collapse of jammed states give a stick-slip nature to the fluctuations which are periodic at small depths but become "stepped" at large depths, a transition that we interpret as a consequence of the long-range nature of the force chains and the finite size of our experiment. Another important finding is that the mean force and the fluctuations appear to be independent of the properties of the contact surface between the grains and the dragged object. These results imply that the drag force originates in the bulk properties of the granular sample.
我们研究了物体在颗粒介质中运动时所受曳力的波动情况。堵塞状态的相继形成和瓦解赋予了波动一种粘滑特性，这种波动在小深度时是周期性的，但在大深度时会变成“阶梯状”，我们将这种转变解释为是力链的长程性质和我们实验的有限尺寸所导致的结果。另一个重要发现是，平均力和波动似乎与颗粒和被拖动物体之间的接触面性质无关。这些结果表明，曳力源自颗粒样品的整体性质。
