Mark Hemphill, University of North Carolina at Chapel Hill


Turbulent Mixing of Vortex Rings in a Stably Stratified Tank

Abstract: Vertical density stratifications are prevalent in both the atmosphere and the ocean. These layers strongly influence the mixing and dispersion properties of particles passing through them. When a fluid droplet falls under the influence of gravity into a bath of a miscible fluid a vortex ring is formed and remains stable to a fairly large penetration depth. This simplified experiment allows for the exploration of a large parameter space in a highly reproducible environment. In this poster a novel set of experiments is reported in which this behavior is studied in the presence of sharply stratified layers. The experiments performed release droplets of varying densities into homogeneous as well as stably stratified tanks. For each run, the release height, eccentricity of the droplet falling in air, and respective maximum depth of penetration were recorded. For the stratified experiments, the vortex ring exhibited one of three behaviors: settling, bouncing which results in complete entrapment, or partial entrapment with core fallout. The parameter space which corresponds to each of these three observed behaviors is presented.

Collaborators: Casey Smith, Cameron Moseley, and Keith Mertens (University of North Carolina at Chapel Hill)

Mentors: Rich McLaughlin and Roberto Camassa (University of North Carolina at Chapel Hill)