title: Stripe formation in granular mixtures due to the differential influence of drag.
abstract: We describe an investigation of fluid-immersed granular mixtures subjected to horizontal vibration. For sufficiently large amplitudes of vibration, a mixture of equal-sized glass and bronze particles in water is found to separate into a striped pattern. Numerical simulations based on soft-sphere molecular dynamics coupled to the interstitial fluid are able to capture many of the features observed experimentally. We propose a general pattern-formation mechanism based on the differential influence of drag on the components of the mixture. An expression for the number of stripes as a function of the system parameters is derived and shown to be in good agreement with experiments.
authors.affiliation: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Sánchez
authors.forename: Michael R
authors.initials: MR
authors.lastname: Swift
authors.forename: P J
authors.initials: PJ
authors.lastname: King