An experimental study of the bulk properties of vortex rings translating through a stratified fluid

Abstract

Experiments are carried out to find the bulk properties and some structural properties of vortex rings in a stratified fluid. Previous theoretical descriptions of vortex ring propagation speed in a homogeneous fluid are compared to experiment and developed for use in stratified fluids. Vortex rings are fired at oblique angles to the horizontal and at different speeds through a stratified fluid. The buoyancy frequency of the fluid is varied between different series of experiments. New models are proposed which predict the speeds and trajectories of vortex rings fired through a stratified fluid and these are compared to experiment. It is shown that these models perform well in high Froude number flows, but less well in low Froude number flows.