Vortex rings are ubiquitous in nature, showing up in droplet impacts, in propulsion, and even in volcanic eruptions….
Vortex rings are ubiquitous in nature, showing up in droplet impacts, in propulsion, and even in volcanic eruptions. Understanding the interaction and breakdown of multiple vortices with one another is therefore key. The image above shows a circular disk that’s being oscillated up and down (in and out of the page). As the disk moves and changes direction, it generates vortices that interact with one another. Here some of those interactions are visualized with fluorescent dye. The overlapping vortices form complex and beautiful shapes on their way to breakdown. (Image credit: J. Deng et al., poster, paper)