A dynamic mechanical model of the vocal folds and tract has been constructed in order to investigate the effect of periodically interrupting a flow of air along a tube. Hotwire anemometer measurements of the fluid movement within the tract have been made. Behaviour close to the shutters is found to vary greatly across the tract cross-section, having the form of a jet surrounded by a vortex ring which widens as it develops to fill the entire tract cross-section by approximately 4 cm downstream of the shutters.