Cross-linking of two vortex rings

Abstract

The mechanism for cross-linking two vortex rings has been investigated experimentally. Phase-locked velocity measurements using x-type hot wires were carried out point by point over the entire flow field, and time-dependent vorticity fields were educed. It is found that a new pair of vortex tubes is created, which connects the interacting vortex rings and grows gradually, while the vorticity intensity of the main rings decreases. This is considered to be a type of bridging phenomenon of the vortex tubes, as proposed by Kida and Takaoka [Phys. Fluids 30, 2911 (1987)] in their numerical simulation.