title: Mach cone in a shallow granular fluid.
abstract: We study the V -shaped wake (Mach cone) formed by a cylindrical rod moving through a thin, vertically vibrated granular layer. The wake, analogous to a shock (hydraulic jump) in shallow water, appears for rod velocities vR greater than a critical velocity c . We measure the half angle theta; of the wake as a function of vR and layer depth h . The angle satisfies the Mach relation, sin theta=c/vR , where c= square root of gh , even for h as small as one-particle diameter.
authors.affiliation: Center for Nonlinear Dynamics and Department of Physics, University of Texas, Austin, Texas 78712, USA. Patrick.Heil@urz.uni-heidelberg.de
authors.forename: Patrick
authors.initials: P
authors.lastname: Heil
authors.forename: E C
authors.initials: EC
authors.lastname: Rericha
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Goldman
authors.forename: Harry L
authors.initials: HL
authors.lastname: Swinney