The Berezinski˘ı-Kosterlitz-Thouless (BKT) essential phase transition in the 2d XY model is revisited. Its mechanism usually described by (un)binding of vortex–anti-vortex (V–AV) pairs, which does, however, not provide a clear-cut quantitative criterion for criticality. Known sharp criteria are divergence correlation length and discontinuity helicity modulus. Here we propose probe new criterion...

Three sudden spin-down events, termed `anti-glitches', were recently discovered in the accreting pulsar NGC 300 ULX-1 by \textit{Neutron Star Interior Composition Explorer} (NICER) mission. Unlike previous anti-glitches detected decelerating magnetars, these are first recorded an accelerating pulsar. One standard theory is that spin-up glitches caused avalanches of collectively unpinning vortic...

The paper presents a design procedure for anti-vortex endplates that are fitted to tip limited blades of the subsonic axial fans utilised in compact cooling units. The authors study the impact of tip leakage vortex bursting on the performance of the studied class of fans. The vortex breakdown occurs in the swirling flows at a blade’s tip, and is found to be a flow feature associated with the pr...

A knot is a circle smoothly embedded in 3-dimensional Euclidean space or its compactification, the 3-sphere. Two knots are regarded as the same if one can be smoothly deformed into the other.1 The mathematical theory of knots emerged from the smoky ruins of Lord Kelvin’s “vortex atom theory,” a hopelessly optimistic theory of matter of the nineteenth century in which atoms appeared as microscop...

Hydrodynamic cavitation (HC) is being increasingly used in a wide range of applications. Unlike ultrasonic cavitation, HC scalable and has been at large scale industrial However, no information about influence on performance available the open literature. In this work, we present for first time, experimental data use degradation complex organic pollutants water four different scales (~200 times...

We demonstrate generation and frequency doubling of unit charge vortices in a linear astigmatic resonator. Topological instability of the double charge harmonic vortices leads to well separated vortex cores that are shown to rotate, and become anisotropic, as the resonator is tuned across resonance.