Screech tones from free and ducted supersonic jets
Abstract
The dependence of the instability wave spectrum on azimuthal mode number, the jet to ambient gas temperature ratio, and the jet Mach number is studied. It is shown that the switch of the dominant screech mode (axisymmetric to helical/flapping) as Mach number increases is due to the switch in dominance of the corresponding mode of instability waves. Super-resonance can occur when the feedback loop is powered by the most amplified instability wave. It is suggested that the large amplitude pressure fluctuations and tone in the test cells are generated by super-resonance.
- Publication:
-
31st AIAA Aerospace Sciences Meeting and Exhibit
- Pub Date:
- January 1993
- Bibcode:
- 1993aiaa.meetR....T
- Keywords:
-
- Ducted Flow;
- Free Jets;
- Sound Pressure;
- Sound Waves;
- Supersonic Jet Flow;
- Mach Number;
- Noise Generators;
- Wave Propagation;
- Acoustics