With multi-stream coannular nozzles, sometimes tones occur that may cause the nozzle to fail noise regulation standards. A two-stream nozzle was studied experimentally and numerically in an at-tempt to identify the sources of such tones and explore remedies. For the given nozzle configuration, sharp tones occurred in a range of low jet Mach numbers. The tones apparently occurred due to a coupling between vortex shedding from the struts, which held the nozzles and the center-body together, with various duct acoustic modes. A leading edge treatment of the struts is shown to eliminate the tones via disruption of the vortex shedding.
Tones Encountered with a Coannular Nozzle and a Method for their Suppression
American Institute of Aeronautics and Astronautics (AIAA) Aviation Forum 2017 ; 2017 ; Denver, CO, United States
2017-06-05
Conference paper
No indication
English