Liao Chun-Chung, Hsiau Shu-San, Wu Chi-Sou
Department of Mechanical Engineering, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan, Republic of China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Dec;86(6 Pt 1):061316. doi: 10.1103/PhysRevE.86.061316. Epub 2012 Dec 26.
This study experimentally investigates the influence of intruder surface roughness in the Brazil nut effect in a quasi-two-dimensional vertical vibration granular bed. The intruder dynamics are determined using a particle-tracking method. The results show that surface roughness has a crucial role in the intruder rise dynamics; a rougher intruder has more difficulty rising in the bed because of higher kinetic energy dissipation. This study determined that penetration length and drag length are reduced and drag is enhanced as intruder surface roughness increases. The exponential decay of the penetration length with vibration frequency is shown. The results also show that at higher dimensionless vibration acceleration and lower vibration frequency the variation in rise time between smooth and rough intruders is negligible.
本研究通过实验研究了准二维垂直振动颗粒床中侵入体表面粗糙度对巴西果效应的影响。使用粒子跟踪方法确定侵入体动力学。结果表明，表面粗糙度在侵入体上升动力学中起着关键作用；由于动能耗散较高，表面较粗糙的侵入体在床层中上升更困难。本研究确定，随着侵入体表面粗糙度增加，穿透长度和拖曳长度减小，拖曳力增强。给出了穿透长度随振动频率的指数衰减关系。结果还表明，在较高的无量纲振动加速度和较低的振动频率下，光滑和粗糙侵入体之间上升时间的差异可忽略不计。
