A comparison of the aeroacoustic characteristics of free and impinging jets with deflected seals noise reduction technique

Scott M. Hromisin, Leighton M. Myers, Dennis K. McLaughlin, Philip J. Morris

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


The present study aims to characterize the dual impinging jet acoustic field in to better understand the noise distribution surrounding military STOVL aircraft during hover landings. Unheated jet measurements are made in a rear supersonic impinging jet exhausting through a CD nozzle operating in tandem with a forward sonic jet. Comparisons are made to supersonic, free jets issuing from the same CD nozzle. Azimuthal angles are compared to equal polar angles and represent the positioning of shipboard around vertically-landing and traditional military aircraft. OASPLs for single and dual impinging jets increased with increasing standoff distance. At the largest standoff heights the impinging jets were louder than free jets in the forward arc by 3-4dB. Both single and dual impinging jet directivities showed the peak noise to be directed towards the forward arc. Operation of the forward, sonic jet had little effect on the jet OASPL and the effect decreased as the operational pressure of the rear nozzle increased. Heat-simulated, dual impinging jet far-field OASPLs had a peak noise emission direction aimed towards the 90-120° arc which was observed to increase to greater angles with decreasing standoff distance. Heat simulated measurements for the 6 deflected seals nozzle showed 2-3dB OASPL of noise reduction in the peak impinging jet noise direction at the two lowest nozzle standoff distances.

Original languageEnglish (US)
Title of host publication54th AIAA Aerospace Sciences Meeting
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624103933
StatePublished - 2016
Event54th AIAA Aerospace Sciences Meeting, 2016 - San Diego, United States
Duration: Jan 4 2016Jan 8 2016

Publication series

Name54th AIAA Aerospace Sciences Meeting


Other54th AIAA Aerospace Sciences Meeting, 2016
Country/TerritoryUnited States
CitySan Diego

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering


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