title: Granular segregation in a thin drum rotating with periodic modulation.
abstract: We present the results of an experimental investigation into the effects of a sinusoidal modulation of the rotation rate on the segregation patterns formed in thin drum of granular material. The modulation transforms the base pattern formed under steady conditions by splitting or merging the initial streaks. Specifically, the relation between the frequency of modulation and the rotation rate determines the number of streaks which develop from the base state. The results are in accord with those of Fiedor and Ottino [J. Fluid. Mech. 533, 223 (2005)10.1017/S0022112005003952], and we show that their ideas apply over a wide range of parameter space. Furthermore, we provide evidence that the observed relationship is maintained for filling fractions far from 50% and generalize the result in terms of the geometry of the granular deposit.
authors.affiliation: Manchester Center for Nonlinear Dynamics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom.
authors.forename: Richard D P
authors.initials: RD
authors.lastname: East
authors.affiliation: Manchester Center for Nonlinear Dynamics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom.
authors.forename: Philippa
authors.initials: P
authors.lastname: McGuinness
authors.affiliation: Manchester Center for Nonlinear Dynamics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom.
authors.forename: Finn
authors.initials: F
authors.lastname: Box
authors.affiliation: Manchester Center for Nonlinear Dynamics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Mullin
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Navarra, 31080 Pamplona, Spain.
authors.forename: Iker
authors.initials: I
authors.lastname: Zuriguel