The nature of bubble entrapment in a Lamb–Oseen vortex

Bubble trajectories in the presence of a decaying Lamb–Oseen vortex are calculated using a modified Maxey–Riley equation. Some bubbles are shown to get trapped within the vortex in quasi-equilibrium states. All the trapped bubbles exit the vortex at a time that is only a function of the Galilei number and the vortex Reynolds number. The set of initial bubble locations that lead to entrapment is numerically determined to show the capturing potential of a single vortex. The results provide insight into the likelihood of bubble entrapment within vortical structures in turbulent flows.