title: Symmetrically periodic segregation in a vertically vibrated binary granular bed.
abstract: Periodic segregation behaviors in fine mixtures of copper and alumina particles, including both percolation and eruption stages, are experimentally investigated by varying the ambient air pressure and vibrational acceleration. For the cases with moderate air pressure, the heaping profile of the granular bed keeps symmetrical in the whole periodic segregation. The symmetrical shape of the upper surface of the granular bed in the eruption stage, which resembles a miniature volcanic eruption, could be described by the Mogi model that illuminates the genuine volcanic eruption in the geography. When the air pressure increases, an asymmetrical heaping profile is observed in the eruption stage of periodic segregation. With using the image processing technique, we estimate a relative height difference between the copper and the alumina particles as the order parameter to quantitatively characterize the evolution of periodic segregation. Both eruption and percolation time, extracted from the order parameter, are plotted as a function of the vibration strength. Finally, we briefly discuss the air effect on the granular segregation behaviors.
authors.affiliation: School of Physics, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Pingping
authors.initials: P
authors.lastname: Wen
authors.affiliation: 1] School of Physics, Beijing Institute of Technology, Beijing 100081, China [2] Key Laboratory of Cluster Science of Ministry of Education, Beijing 100081, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zheng
authors.affiliation: Science and Technology on Electromagnetic Scattering Laboratory, Beijing 100854, China.
authors.forename: Liangsheng
authors.initials: L
authors.lastname: Li
authors.affiliation: School of Physics, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Qingfan
authors.initials: Q
authors.lastname: Shi