title: Spin Brazil-nut effect and its reverse in a rotating double-walled drum.
abstract: The segregation of binary mixtures in a filled rotating double-walled drum is explored by simulations. Based on the characteristics of self-gravity and the centrifugal force, we argue that both percolation and buoyancy effects dominate the segregation process. The simulational results show that up to long enough times the segregation state is controlled by the rotational speed, the particle radius and density. At low rotational speeds, the smaller and heavier particles tend to accumulate towards the inner drum wall and the bigger and lighter ones towards the outer drum wall, while the segregation pattern reverses completely at higher rotational speeds. Two typical phase diagrams in the space of the density and radius ratio of bigger particles to smaller particles further confirm the predictions.
authors.affiliation: Department of Applied Physics, Nanjing University of Science and Technology, 210094 Nanjing, China. hdc@njust.edu.cn
authors.forename: Decai
authors.initials: D
authors.lastname: Huang
authors.forename: Ming
authors.initials: M
authors.lastname: Lu
authors.forename: Surajit
authors.initials: S
authors.lastname: Sen
authors.forename: Min
authors.initials: M
authors.lastname: Sun
authors.forename: Yaodong
authors.initials: Y
authors.lastname: Feng
authors.forename: Anna
authors.initials: A
authors.lastname: Yang