title: Wavy Taylor vortices in molecular dynamics simulation of cylindrical Couette flow.
abstract: Molecular dynamics simulations of flow between concentric rotating cylinders are performed. As the relative speed between the two cylinders is increased, a spontaneous flow bifurcation occurs and vortices form in a stationary-vortex or traveling-wavy-vortex configuration. The former emerges when the axial boundary conditions constrain the flow by reflection, and the traveling-wavy-vortex flow develops when the axial boundaries are relaxed to periodic conditions. The flow bifurcation is triggered by the thermal fluctuations in the system, and the resulting flow field is in agreement with previous experimental observations. In addition, the temporal growth of the Fourier mode that characterizes the wavy-vortex motion is well described by Landau's theory for Hopf bifurcations. The spatiotemporal energy spectrum is evaluated in order to characterize the instability in terms of its azimuthal wave number and wave speed.
authors.affiliation: Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom.
authors.forename: David J
authors.initials: DJ
authors.lastname: Trevelyan
authors.affiliation: Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom.|Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
authors.forename: Tamer A
authors.initials: TA
authors.lastname: Zaki