Farkas Z, Tegzes P, Vukics A, Vicsek T
Department of Biological Physics, Eötvös University, Budapest, Pázmány P. Stny 1A, 1117 Hungary.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1999 Dec;60(6 Pt B):7022-31. doi: 10.1103/physreve.60.7022.
Motivated by recent advances in the investigation of fluctuation-driven ratchets and flows in excited granular media, we have carried out experimental and simulational studies to explore the horizontal transport of granular particles in a vertically vibrated system whose base has a sawtooth-shaped profile. The resulting material flow exhibits novel collective behavior, both as a function of the number of layers of particles and the driving frequency; in particular, under certain conditions, increasing the layer thickness leads to a reversal of the current, while the onset of transport as a function of frequency occurs gradually in a manner reminiscent of a phase transition. Our experimental findings are interpreted here with the help of extensive, event driven Molecular Dynamics simulations. In addition to reproducing the experimental results, the simulations revealed that the current may be reversed as a function of the driving frequency as well. We also give details about the simulations so that similar numerical studies can be carried out in a more straightforward manner in the future.
受近期波动驱动的棘轮效应以及激发颗粒介质中流动研究进展的启发，我们开展了实验和模拟研究，以探索颗粒在底部具有锯齿形轮廓的垂直振动系统中的水平输运。所产生的物质流呈现出新颖的集体行为，这是颗粒层数和驱动频率的函数；特别是在某些条件下，增加层厚会导致电流反转，而作为频率函数的输运起始以类似于相变的方式逐渐发生。我们在此借助广泛的、事件驱动的分子动力学模拟来解释实验结果。除了重现实验结果外，模拟还表明电流也可能作为驱动频率的函数而反转。我们还给出了模拟的详细信息，以便未来能以更直接的方式开展类似的数值研究。
