エッジトーン発振現象

発振波からの考察

抄録

This paper deals with the characteristics of the oscillating amplitude, the frequency jumping phenomenon, and the pressure gradient of an edgetone oscillation.
In this study, the oscillating waveform is discussed from the pressure change detected at the apex of the wedge, and the characteristics of the waveform and the oscillating amplitude are investigated experimentally with respect to the jet deflection, the jet velocity profile, and the nozzle-edge distance.
Frequency jumping is discussed by referring to the results obtained by analyzing the oscillating waveform with a spectrum analyzer. The pressure change at the apex of the wedge is regarded as being due to the behavior of the pressure source, and the relation between the pressure gradient and the jet deflection is discussed on the basis of the pressure amplitude characteristics.
The following facts are confirmed.
The amplitude characteristics are very much affected by the jet deflection and the velocity profile at the apex of the wedge. The oscillating waveform contains the frequencies of the various stages, and frequency jumping is related to the amplitude characteristics of each stage. The relation between the pressure gradient and the jet deflection is different from that of the models which have been assumed.