In this paper, we show that improved air circulation above a heat sink is possible using thin winglet-type vortex generators that can be passively retrofitted to an existing unit. By mounting these vortex generators on the leading edge of heat sink fins, pairs of counterrotating vortices are induced within the interfin spacing. The vortices disturb the boundary layers and serve to mix the air i...

We study propagation of a pair of oppositely charged and mutually incoherent vortices in anisotropic nonlinear optical media. Mutual interactions retard the delocalization of the vortex core observed for isolated vortices.

Singly quantized vortices have already been observed in many systems, including the superfluid helium, Bose-Einstein condensates of dilute atomic gases, and condensates of exciton-polaritons in the solid state. Two-dimensional superfluids carrying spin are expected to demonstrate a different type of elementary excitations referred to as half-quantum vortices, characterized by a pi rotation of t...

The dynamics of magnetostatically coupled vortices in ferromagnetic two-dimensional (2D) nanodisk arrays is theoretically investigated using the rigid vortex model and Thiele’s equation whereby the circular motion with the lowest energy for each vortex core is described. We present here dispersion relations and density of states for eigenfrequencies of coherently rotating vortices with ordered ...

A high-resolution stereoscopic particle image velocimetry (PIV) system was used to conduct three-dimensional measurement of an air jet exhausted from a lobed nozzle. The characteristics of the mixing process in the lobed jet  ow are revealed clearly and quantitatively from the stereoscopic PIV measurement results. The instantaneous velocity and streamwise vorticity distributions revealed that ...

It is of great theoretical interest to investigate the interaction between ames and vortices as a model problem to study turbulent combustion because a eld of turbulence can be considered as an ensemble of vortices of various length and time scales. Interaction between ames and vortices governs the rate of combustion and results in di erent types of instabilites. The goal of this study is to un...

This paper demonstrates that analytical solutions to the steady two-dimensional Euler equations possessing all the qualitative properties of multipolar vortices observed experimentally and numerically can be constructed using the theory of algebraic curves and quadrature domains. The solutions consist of a finite set of line vortices superposed on finite-area patches of uniform vorticity. By wa...

Pure electron plasma columns are contained inside hollow conducting cylinders in an axial magnetic field. In the 2D E3B drift approximation, an electron column is a vortex evolving in (r ,u) according to the Euler equation. First the center-of-mass orbits of two vortices sufficiently well-separated to be stable to merger are characterized. Equilibria are observed in which the vortices orbit abo...

Transistors constitute the backbone of modern day electronics. Since their advent, researchers have been seeking ways to make smaller and more efficient transistors. Here, we demonstrate a sustained amplification of magnetic vortex core gyration in coupled two and three vortices by controlling their relative core polarities. This amplification is mediated by a cascade of antivortex solitons tra...

We examine the spectrum of small perturbations around global and local (gauge) abelian vortices, using simple numerical matrix techniques. The results are of interest both for cosmic strings and for their condensed matter analogues, superfluid and superconductor vortices. We tabulate the instabilities of higher winding number vortices, and find several bound states. These localised coherent osc...