By means of electrical transport measurements we have studied the rectified motion of vortices in ratchet potentials engineered on overdamped Josephson junction arrays. The rectified voltage as a function of the vortex density shows a maximum efficiency close a matching condition to the period of the ratchet potential indicating a collective vortex motion. Vortex current reversals were detected...

The linear stability of thin vortex rings are studied by short-wavelength stability analysis. The modified Hill–Schrödinger equation for vortex rings, which incorporates curvature effect, is derived. It is used to evaluate growth rates analytically. The growth rates are also evaluated by numerical calculation and they agree well with analytical values for small e which is the ratio of core radi...

The circular polarization components of a vortex beam in a uniaxial crystal exhibit complex propagation characteristics. We demonstrate how the amount of splitting may be distinguished by use of a vortex beam. We predict and experimentally verify a threshold angle subtending the crystal and beam axes, below which the splitting is indistinguishable.

We propose very general vortex nucleation mechanismss1] analogous to a hydrodynamic instability and calculate associated critical velocity in agreement with experiments. The creation of vortices via extrinsic mechanism is driven by a formation of the surface vorticity sheet created by the ow, which reaches a critical size. Such a sheet screens an attraction of a half-vortex ring to the wall, th...

Two-dimensional vortex sheet suffers an unstable deformation from the Kelvin–Helmholtz instability and a curvature singularity which develops in a finite time. In this paper, long time computations of the two-dimensional vortex sheet are performed by a robust and efficient numerical method with high accuracy. To handle the rapid and non-uniform stretching of the interface, we adopt the adaptive...

In today's CFD-assisted turbomachinery design, a primary objective is to minimize the effects of vortices. Their automatic identification, along with other flow structures, in numerical data is a current research topic. This paper presents a novel method to find vortex hulls in turbomachinery flows automatically. Based on a vortex core line that is the centerline of the vortex, the method is ab...

The discrete shell structure of vortex matter strongly influences the flux dynamics in mesoscopic superconducting Corbino disks. While the dynamical behavior is well understood in large and in very small disks, in the intermediate-size regime it occurs to be much more complex and unusual, due to (in)commensurability between the vortex shells. We demonstrate unconventional vortex dynamics (inver...

Experiments performed with different vortex pump beams show for the first time the algebra of the vortex topological charge cascade, that evolves in the process of nonlinear wave mixing of optical vortex beams in Kerr media due to competition of four-wave mixing with self-and cross-phase modulation. This leads to the coherent generation of complex singular beams within a spectral bandwidth larg...

A numerical investigation is conducted to study flow structures and interactions that are caused by a pitched synthetic jet placed in a laminar (Blasius) boundary layer with zero pressure gradient. Simulations are performed for various permutations of jet parameters including pitch angle (i.e., θ=60, 75, and 90), blowing ratio (i.e., Cb = 0.5, 1.0, 1.5, and 2.0), and non-dimensional actuation f...

Using density functional theory, we investigate the structure of mixed (3)He(N3)-(4)He(N4) droplets with an embedded impurity (Xe atom or HCN molecule) which pins a quantized vortex line. We find that the dopant+vortex+(4)He(N4) complex, which in a previous work [F. Dalfovo et al., Phys. Rev. Lett. 85, 1028 (2000)] was found to be energetically stable below a critical size N(cr), is robust agai...