On the Dispersion Relation of a Vortex Cavity Free

A dispersion relation of a vortex cavity describes the relation between spatial wave numbers and frequencies of perturbations of the cavity radius. The paper presents an update of the theory and the interpretation of experimental data for the dispersion relation of a vortex cavity as presented by Pennings et al. Especially, the standing wave pattern generated by the attachment of the cavity to the foil is now identified in the theoretical and experimental wave number-frequency diagram.