Vortex line topology during vortex tube reconnection

TL;DR

This paper investigates the complex topology of vortex lines during tube reconnection, revealing new features like flux rings, null points, and internal reconnections, and introduces a robust measurement of reconnection rates in three-dimensional flows.

Contribution

It provides new insights into vortex line topology during reconnection, including the generation of flux rings and null points, and extends understanding to fully three-dimensional vortex interactions.

Findings

Discovered generation of small flux rings during reconnection.

Identified internal vortex line reconnections within tubes.

Showed that adding a third vortex tube makes the process fully three-dimensional.

Abstract

This paper addresses reconnection of vortex tubes, with particular focus on the topology of the vortex lines (field lines of the vorticity). This analysis of vortex line topology reveals previously undiscovered features of the reconnection process, such as the generation of many small flux rings, formed when reconnection occurs in multiple locations in the vortex sheet between the tubes. Consideration of three-dimensional reconnection principles leads to a robust measurement of the reconnection rate, even once instabilities break the symmetry. It also allows us to identify internal reconnection of vortex lines within the individual vortex tubes. Finally, the introduction of a third vortex tube is shown to render the vortex reconnection process fully three-dimensional, leading to a fundamental change in the topological structure of the process. An additional interesting feature is the generation of vorticity null points.