title: Anomalous Sinking of Spheres due to Local Fluidization of Apparently Fixed Powder Beds.
abstract: The sinking of an intruder sphere into a powder bed in the apparently fixed bed regime exhibits complex behavior in the sinking rate and the final depth when the sphere density is close to the powder bed density. Evidence is adduced that the intruder sphere locally fluidizes the apparently fixed powder bed, allowing the formation of voids and percolation bubbles that facilitates spheres to sink slower but deeper than expected. By adjusting the air injection rate and the sphere-to-powder bed density ratio, this phenomenon provides the basis of a sensitive large particle separation mechanism.
authors.affiliation: Department of Applied Chemistry, Okayama University, Okayama 700-8530, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Oshitani
authors.affiliation: Department of Applied Chemistry, Okayama University, Okayama 700-8530, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka Suita, Osaka 565-0871, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Tsuji
authors.affiliation: Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka Suita, Osaka 565-0871, Japan.
authors.forename: Kyohei
authors.initials: K
authors.lastname: Higashida
authors.affiliation: School of Mathematics and Statistics, University of Melbourne, Parkville 3010, Australia.|Department of Chemistry and Biotechnology, Swinburne University of Technology, Hawthorn 3122, Australia.
authors.forename: Derek Y C
authors.initials: DY
authors.lastname: Chan