Abstract
Intending to develop a impact plane bending fatigue testing machine without mechanical moving part, a fluidic oscillator using supersonic bistable device has been design and tested.
The newly developed oscillator is a kind of the loaded oscillator which has the bifurcated outlet channels with load capacitances. As load capacitances, tanks or tubes are used to control the oscillating frequency. The main outlet ducts construct opposing nozzles, so that the output jet can keep the high power without losing energy through the load capacitances. A fatigue test piece is set between the opposing nozzles forming flapper-nozzle configuration and is vibrated by the alternately impinging jets.
It was revealed that a non-attachment device, ie, without load, the main jet flows equally into both outlets, is necessary for realizing the supersonic oscillator. The oscillation starts when the pressure in the load tank and that in the outlet duct increase up to the same value, viz., switching back pressure. The frequency of the oscillation is controlled independently of the supply pressure by using tubes as the load capacitances.
