An experimental study of scalar mixing in a laminar vortex is presented for vortices generated between two gas streams flowing parallel to each other in a rectangular flow channel. An isolated line vortex is initiated on demand by momentarily increasing one stream velocity in relation to the other using an electromagnetically actuated piston. The temporal piston motion profile is tailored to ge...

For a model with isotropic nearest neighbor exchange combined with easy-plane exchange or single-ion anisotropies, the static effects of a magnetic vacancy site on a nearby magnetic vortex are analyzed on square, hexagonal and triangular lattices. Numerical energy minimization and linear stability analysis using the vortex instability mode are employed. When the vortex is centered on a vacancy,...

for a long time, many efforts have been taken on improving gas turbine performance to increase the propulsive force and keep the chamber walls cool. in this regard, implementation of cyclonic and vortex engines have been proposed. according to increasing in the engine efficiency and keeping the chamber walls cool, the bidirectional vortex flow which is exited in the vortex engine, makes researc...

Wingtip vortex flow is of great importance because of its effect on practical problems such as landing separation distances for aircraft, blade/vortex interactions on helicopter blades, and propeller cavitations on ships. Extensive investigations have been conducted to improve the understanding of the tip vortex structure and its dissipation or persistence analytically, numerically, and experim...

Nonlinear vortex excitations in models for layered or two-dimensional (2D) magnets [1] have attracted much study not only for their role in the thermodynamics of the Berezinskii-Kosterlitz-Thouless vortex-unbinding transition [2,3], but more recently because their microscopic dynamic behavior is not fully understood. The dynamics of individual vortices continues under study for ferromagnets (FM...

An experimental study of the turbulent near wake of a rotating circular cylinder was made at a Reynolds number of 2000 for velocity ratios, λ between 0 and 2.7. Particle image velocimetry data are analyzed to study the effects of rotation on the flow structures behind the cylinder. The results indicate that the rotation of the cylinder causes significant changes in the vortex formation. Kármán ...

We present high-performance and high-accuracy numerical simulations of quantum turbulence modelled by the Gross–Pitaevskii equation for time-evolution macroscopic wave function system. The hydrodynamic analogue this model is a flow in which viscosity absent all rotational carried quantized vortices with identical topological line-structure circulation. Numerical start from an initial state cont...

Recently, extensive vortex lattice metastability was reported in MgB2 in connection with a second-order rotational phase transition. However, the mechanism responsible for these well-ordered metastable vortex lattice phases is not well understood. Using small-angle neutron scattering, we studied the vortex lattice in MgB2 as it was driven from a metastable to the ground state through a series o...

Magnetic vortex is one of the simplest topologically non-trivial textures in condensed matter physics. It is the ground state of submicron magnetic elements (dots) of different shapes: cylindrical, square etc. So far, the vast majority of the vortex dynamics studies were focused on thin dots with thickness 5-50 nm and only uniform across the thickness vortex excitation modes were observed. Here...

We give two fundamental solutions for the motion of a point vortex near a flexible wall, up to first order in wall deflection, using computational methods. For a point vortex near an infinite horizontal wall, the deformation of the wall intensifies the flow at the wall near the vortex, and increases the speed of the vortex. Near a circular wall there is a strong mutual amplification of the defl...