This research deals with the switching mechanism of a flip-flop jet nozzle with a connecting tube, which is based on the measurements of pressure in two chambers, velocity in the connecting tube and velocity distribution between two inside walls of the nozzle, i. e., reattachment walls. The authors particularly focus on the details of switching flow field inside the nozzle, using a Ultrasound-Velocity-Profile monitor (UVP monitor). As a result, two re-circulating flows, viz., two vortical structures, are shown on both side walls inside the nozzle. By means of the simultaneous observation of chamber pressures and connecting-tube velocity with UVP results, we show a coherent scenario of this jet-oscillation phenomenon.
