Mass, angular momentum, and energy budgets are examined in an analytical model of vortex merging relevant to midlatitude mesoscale eddies. The vortices are baroclinic and cyclogeostrophic. The fluid surrounding them is assumed to remain quiescent. It is shown that due to this surrounding fluid, angular momentum is conserved when expressed in both the inertial and rotating frames of reference. L...

Our experiments show that the critical power for self-focusing collapse of femtosecond vortex beams in air is significantly higher than that of a flattop beam and grows approximately linearly with the vortex order. With less than 10% of initial transverse intensity modulation of the beam profiles, the dominant mode of self-focusing collapse is the azimuthal breakup of the vortex rings into indi...

[1] United Kingdom Meteorological Office global analyses from 1991 to 2001 are used to create a global climatology of stratospheric polar vortices and anticyclones. New methodologies are developed that identify vortices in terms of evolving three-dimensional (3-D) air masses. A case study illustrates the performance of the identification schemes during February and March of 1999 when a merger o...

The short wave instability on corotating vortex filaments is investigated. It is shown that the short wave instability always occurs on corotating vortex filaments of fixed core structure. Moreover, when the interfilament distance is smaller than or comparable to the core size, vortex filaments produce short wave unstable modes which lead to wild stretching and folding; when vortex filaments ar...

We study the stability of vortices in trapped single-component Bose–Einstein condensates within self-consistent mean-field theories; in particular, we consider the Hartree–Fock–Bogoliubov–Popov theory and its recently proposed gapless extensions. It is shown that for sufficiently repulsively interacting systems the anomalous negative-energy modes related to vortex instabilities are lifted to po...

surface. I n today’s cost-conscious air transportation industry, fuel costs are a substantial economic concern. Drag reduction is an important way to increase fuel efficiency and reduce these costs. Even a 5% reduction in drag translates into estimated savings of millions of dollars in annual fuel costs. Organized structures that play an important role in turbulence transport may cause large sk...

The present study dealt with the wall static pressure of a rectangular curved duct with angle of turn 90° at all four faces with various locations. The normalized wall static pressure distributions at the top, bottom, inside and outside surfaces of the C-duct are drawn in the form of contours at three different air velocities, Uav = 20m/s, 40m/s and 60m/s respectively. These iso-bar contours in...

In this paper, we describe new techniques for detecting vortices and regions of separated flow with application to visualization of large-scale computational fluid dynamics data sets. The vortex core detection algorithm is based on ideas derived from combinatorial topology, specifically, Sperner’s lemma. The algorithm to detect regions of separated flow is based on the assumption that each pair...

We demonstrate experimentally the formation of polychromatic single- and double-charge optical vortex solitons by employing a lithium niobate crystal as a nonlinear medium with defocusing nonlinearity. We study the wavelength dependence of the vortex core localization and observe self-trapping of polychromatic vortices with a bandwidth spanning over more than 70 nm for single-charge and 180 nm ...