抄録
In this paper, we experimentally verify a new model to predict the predominant frequency of acoustic oscillations in supersonic flows over a rectangular cavity. This model was developed previously in order to understand why the jump in the predominant frequency occurred when the length-to-depth ratio of the cavity was gradually varied. In the experiment, the target flow is supersonic flows over a rectangular cavity with the inlet Mach number of 1.7. The length-to-depth ration of the cavity is varied by changing the depth with the length constant. The oscillation in pressure is measured by the semiconductor type pressure sensor mounted on the wall downstream of the trailing edge of the cavity. The power spectral density is calculated from the time-dependent pressure signals and then the predominant frequencies are obtained for each cavity depth. Also, the predominant frequencies are calculated by using the model for each experimental condition. The results obtained by using the model are found to agree with the experimental results with respect to both the frequency jump and the variation in frequency with the length-to-depth ratio.
