Aerodynamicists and biologists have long recognized the benefits of formation flight. When birds or aircraft fly in the upwash region of the vortex generated by leaders in a formation, induced drag is reduced for the trail bird or aircraft, and efficiency improves. The major consequence of this is that fuel consumption can be greatly reduced. When two aircraft are separated by a large enough lo...

In this study, a new method for manipulating energy flow in 3D vector field is proposed. method, an azimuthally-polarized beam with noncanonical vortex, the X-type focused high-numerical aperture system. It found that, instead of invariance which characteristic traditional vortex (i.e., canonical vortex), both longitudinal and transverse flows virtue rotate around center as propagates, rotation...

The three-dimensionality of the velocity field in the wake of a circular cylinder has excited considerable interest and debate over the past decade. Presented here are experimental results that characterize the underlying vorticity field of such wakes. Using particle image velocimetry (PIV), instantaneous velocity fields were measured and from these the vorticity of the longitudinal vortices ly...

We use the three dimensional uniformly frustrated XY model as a model for a high temperature superconductor in an applied magnetic field and explicitly measure the longitudinal correlation length jz in the vortex line liquid phase. We determine the scaling of jz with magnetic field and system anisotropy close to the vortex lattice melting transition. We apply our results to determine the extent...

In this paper, the oscillating two-dimensional laminar flow about a cylinder and the oscillation of a cylinder in still water are studied. A finite volume method is applied to solve the Navier Stokes equations using SIMPLEC algorithm on a body fitted co-located O-type grid. In this study, the non-dimensional flow numbers, Keulegan-Carpenter and Stokes’ numbers are chosen over a range where diff...

Comment on " Longitudinal Superconductivity in Vortex-Line Phases: A Monte Carlo Study " In a recent Letter [1], Carneiro reports on new simulations of vortex-line fluctuations in a London type II su-perconductor with a finite magnetic penetration length l. He concludes that superconductivity parallel to the applied magnetic field H (" longitudinal superconductiv-ity ") vanishes at the same tem...

We show that conservation of longitudinal magnetization in a spinor condensate provides a stabilizing mechanism for a coreless vortex phase-imprinted on a polar condensate. The stable vortex can form a composite topological defect with distinct small- and large-distance topology: the inner ferromagnetic coreless vortex continuously deforms toward an outer singular, singly quantized polar vortex...

A von Karman vortex street generated in the usual way was subjected to a deceleration, thereby changing the ratio of longitudinal to lateral spacing between the vortices. Distortion of the individual vortices followed which resulted in annihilation of concentrated vortex regions and creation of a stationary wake flow. This wake flow was itself dynamically unstable and developed into a new vorte...

Here the hollow vortex Gaussian beam is described by the exact solution of the Maxwell equations. By means of the method of the vectorial angular spectrum, analytical expressions of the electromagnetic fields of a hollow vortex Gaussian beam propagating in free space are derived. By using the electromagnetic fields of a hollow vortex Gaussian beam beyond the paraxial approximation, one can calc...