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This paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow discharged from a convergent-divergent nozzle.The noise phenomenon of flow is generated by an emission of ’transonic tones’.The results obtained show that the frequency of a transonic tone,that differs from the frequency of a screech tone due to the shock-cell structures in a jet and originates in the shock wave in the nozzle,increases in proportion to the nozzle pressure ratio.The high-order transonic tone has the directivity in the direction of the flow.As for the transonic tone’s frequency,the separated zone was calculated by using a simple flow model considering the propagating perturbation.The results of the model corresponded to the results of this experiment well.
This paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow discharged from a convergent-divergent nozzle. The noise phenomenon of flow is generated by an emission of ’transonic tones’. The results obtained show that the frequency of a transonic tone, that differs from the frequency of a screech tone due to the shock-cell structures in a jet and originates in the shock wave in the nozzle, increases in proportion to the nozzle pressure ratio. the high-order transonic tone has the directivity in the direction of the flow. As for the transonic tone’s frequency, the separated zone was calculated by using a simple flow model considering the propagating perturbation. The results of the model corresponded to the results of this experiment well.