title: Stick-slip fluctuations in granular drag.
abstract: We study fluctuations in the drag force experienced by an object moving through a granular medium. The successive formation and collapse of jammed states give a stick-slip nature to the fluctuations which are periodic at small depths but become "stepped" at large depths, a transition that we interpret as a consequence of the long-range nature of the force chains and the finite size of our experiment. Another important finding is that the mean force and the fluctuations appear to be independent of the properties of the contact surface between the grains and the dragged object. These results imply that the drag force originates in the bulk properties of the granular sample.
authors.affiliation: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: I
authors.initials: I
authors.lastname: Albert
authors.forename: P
authors.initials: P
authors.lastname: Tegzes
authors.forename: R
authors.initials: R
authors.lastname: Albert
authors.forename: J G
authors.initials: JG
authors.lastname: Sample
authors.forename: A
authors.initials: A
authors.lastname: Barabási
authors.forename: T
authors.initials: T
authors.lastname: Vicsek
authors.forename: B
authors.initials: B
authors.lastname: Kahng
authors.forename: P
authors.initials: P
authors.lastname: Schiffer