Amagnetic nanoparticle in a vortex state is a promising candidate for the information storage. One bit of information corresponds to the upward or downward magnetization of the vortex core (vortex polarity). The dynamics of the magnetic vortex driven by a spin current is studied theoretically. Using a simple analytical model and numerical simulations, we show that a nondecaying vortex motion ca...

In this study the augmentation of heat transfer in a rectangular channel with triangular vortex generators is evaluated. The span wise averaged Nusselt number, mean temperature and total heat flux are compared with and without vortex generators in the channel at a blade angle of 30° for Reynolds numbers 800, 1200, 1600, and 2000. The use of vortex generators increases the span wise averaged Nus...

This article reviews some recent simulations of vortex sheet roll-up using the vortex blob method. In planar and axisymmetric flow, the roll-up is initially smooth but irregular small-scale features develop later in time due to the onset of chaos. A numerically generated Poincaré section shows that the vortex sheet flow resembles a chaotic Hamiltonian system with resonance bands and a heterocli...

We study the propagation properties of a single vortex in square Josephsonjunction arrays (JJA) with free boundaries and subjected to an applied dc current. We model the dynamics of the JJA by the resistively and capacitively shunted junction (RCSJ) equations. For zero Stewart-McCumber parameter βc we find that the vortex always escapes from the array when it gets to the boundary. For βc ≥ 2.5 ...

This study presents an innovative and simple way to increase the rate of heat transfer in a spiral plate heat exchanger model. Several circular cross-section rods, as continuous vortex generators, have been inserted within the spiral plate heat exchanger in the cross-stream plane. The vortex generators are located at various azimuth angles of α=30◦, 60◦, 90◦, and 120◦ with non-dimensional diame...

Hypersonic airbreathing propulsion for access to space has several advantages over conventional rockets. However, to achieve the theoretical propulsion efficiencies, many technological challenges, such as fast and efficient mixing of the fuel with air, still need to be resolved. Several scramjet inlet geometries naturally generate vortices that could be used for mixing enhancement. Thorough cha...

Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU Abstract Strong perturbations of the Arctic stratosphere during the winter 2002/2003 by planetary waves led to enhanced stretching and folding of the vortex. On two occasions the vortex in the lower stratosphere split into two secondary vortices that re-mer...

In two-dimensional (2D) inviscid incompressible flow, low background vorticity distribution accelerates intense vortices (clumps) to merge each other and to array in the symmetric pattern which is called “vortex crystals”; they are observed in the experiments on pure electron plasma and the simulations of Euler fluid. Vortex merger is thought to be a result of negative “temperature” introduced ...

Point vortex, first introduced by Helmholtz in 1958, is a classic model in two-dimensional incompressible fluid dynamics. The solutions to the equations of various configurations of point vortices have provided many insightful findings in various physical fields involved with vortex dynamics, such as atomic structure, large scale weather patterns and superconductors, etc (Aref 1988). One kind o...

The Investigation of the temporal behavior of coherent structures is a complex process. Particularly when vortices and their temporal change of strength or spatial extents are considered, a pure tracking of vortical structures is insufficient. The exploration of such properties makes it necessary to take into account the interaction between individual coherent structures, also called vortex dyn...