垂直振动作用下二元混合颗粒分层的动态循环反转  

Cycle of segregation patterns in vertically vibrated binary granular mixtures

作　　者：梁宣文[1] 李粮生[1] 侯兆国[1] 吕震[1] 杨雷[1] 孙刚[2] 史庆藩[1] 

机构地区：[1]北京理工大学物理系,北京100081 [2]中国科学院物理研究所,北京100080

出　　处：《物理学报》2008年第4期2300-2305,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10675018,10674157)资助的课题~~

摘　　要：在对垂直振动下的铜颗粒和氧化铝颗粒混合物的研究中,除了观测到巴西果分层和混合分层外,还发现了一种新的随时间周期变化的分离形态.此分离形态可随着时间的演化,在巴西果、反巴西果和三明治这几种分层构型之间进行动态的循环反转.给出了这种反转态出现的相区,并且观测了其动态转变的规律.根据碰撞、磨擦及空气的耗散作用所产生的耗散结构对循环反转态的出现给出了定性的解释,并通过实验证实这种分层构型与空气的存在有密切的关系.A new phenomenon of granular segregation is observed, in which the binary granular mixture submitted to the vertically vibration behaves in cyclic segregation patterns which switches between the Brazil nut, reverse Brazil nut and sandwich patterns with a frequency that accelerates with time. The rule of cycing is investigated, and the phase diagram is depicted. The new phenomenon is qualitatively explained in terms of the collision, friction and air dissipation, and it was experimentally verified that the cycling of segregation patterns has close relation with the presence of air.

关 键 词：颗粒物质 巴西果效应 相分离 

分 类 号：O347.7[理学—固体力学]