We study the disordered, multispiral solutions of two-dimensional oscillatory media for parameter values at which the single-spiral/vortex solution is fully stable. Using the complex Ginzburg-Landau (CGLE) equation, we show that these states, heretofore believed to be static, actually evolve extremely slowly. This is achieved via a reduction of the CGLE to the evolution of the sole vortex coord...

It is shown that the complex Ginzburg-Landau (CGL) equation on the real line admits nontrivial 2-periodic vortex solutions that have 2n simple zeros (\vortices") per period. The vortex solutions bifurcate from the trivial solution and inherit their zeros from the solution of the linearized equation. This result rules out the possibility that the vortices are determining nodes for vortex solutio...

Theoretical aspects of multicomponent superconductivity and systems with competing interactions are studied using Monte Carlo techniques. Motivated by recent experimental and theoretical results of complex structure formation of vortices in multicomponent systems, possible vortex structure formations due to vortex interactions that are not purely attractive or repulsive are considered. Vortex s...

New method of introducing vortex lines of the electromagnetic field is outlined. The vortex lines arise when a complex Riemann-Silberstein vector (E + iB)/ √ 2 is multiplied by a complex scalar function φ. Such a multiplication may lead to new solutions of the Maxwell equations only when the electromagnetic field is null, i.e. when both relativistic invariants vanish. In general, zeroes of the ...

We investigate the physics of the microwave response in YBa2Cu3O7−δ, SmBa2Cu3O7−δ and MgB2 in the vortex state. We first recall the theoretical basics of vortex-state microwave response in the London limit. We then present a wide set of measurements of the field, temperature, and frequency dependences of the vortex state microwave complex resistivity in superconducting thin films, measured by a...

For the first time since Lord Kelvin’s original conjectures of 1875 we address and study the time evolution of vortex knots in the context of the Euler equations. The vortex knot is given by a thin vortex filament in the shape of a torus knot Tp,q (p > 1, q > 1; p, q co-prime integers). The time evolution is studied numerically by using the Biot–Savart (BS) induction law and the localized induc...

A highly accurate Fourier-Chebyshev spectral collocation method has been used to simulate flow in the wake of a sphere in the Reynolds number range from 350 to 650. Flow visualizations and frequency spectra provide a glimpse of the complex vortex dynamics that are observed in the sphere wake. It is found that in addition to the vortex shedding frequency which corresponds to the shedding of larg...

To understand the physics of the complex vortex flow field of the F/A-18 aircraft during maneuvering at high incidences, a series of flow visualizations were conducted in the IAR 0.38 x 0.51m water tunnel. A 1/72-scale model was tested on the new orbital-platform rotary apparatus at angles of attack from 20o to 65o with sideslip angles in the range 10 . It was found that the aerodynamic behavio...

The interaction of a premixed methane/air flame with a counter-rotating vortex pair is analyzed using a parallel low-Mach-number computational model that is based on a detailed C1C2 chemical mechanism. Attention is focused on the transient response of the heat release rate and the flame structure at the centerline of the vortex pair. Results are obtained for vortex pairs of different strengths ...

in many industrial equipment such as boilers and heat exchangers, the cylindrical tubes are exposed to the gas- liquid two phase flow. for any immersed body in flow field vortex shedding is created with a frequency that may be constant or variable, according to conditions such as flow rates, geometry of body, and etc. the failure will happen in the equipment, when this frequency is close to one...