On the oscillation in the bistable fluid amplifier

There is a phenomenon making the internal flow in the wall-attachment fluid amplifier unstable. That is, a jet issued from the nozzle exit causes a continuous switching action between two side walls, and attachment of the jet to the walls becomes unstable. This unstable phenomenon is often observed when the fluid amplifier has a relatively large offset distance and a small splitter distance. This seems to be a kind of oscillation since it has almost constant periods. The frequency of the oscillation is low and it is changeable slightly when either the offset distance or the splitter distance changes. Hence, this unstable phenomenon can be used for a low frequency oscillator in practice. Geometrical shapes of the fluid amplifier having this unstable phenomenon are measured and frequencies are also measured.