Jet noise suppression using flexible filaments-review

E. J. Gutmark, B. Callender, B. A. Anderson, T. R S Bhat, Israel J Wygnanski

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

Abstract

This paper describes the flow structure modifications and reduction in acoustic emissions affected by suspending flexible filaments within the center of supersonic and subsonic jets. Experiments performed with cold subsonic and underexpanded supersonic jets show that the filaments change the flow structure of the jet and may extract energy from the flow, converting the flow energy into filament vibrational / mechanical energy. Changes to the flow structure induced by the filament include weakening of the shock structure in the supersonic jet, and reduction in the mean velocity and turbulence intensity in the subsonic jet. The changes to the jet structure enable a decrease in the noise generation of the jet. Shock related and turbulent mixing noise was reduced up to 35dB for the supersonic jet, and low to mid frequency noise was reduced up to 3dB for the subsonic jet. For the subsonic jet, the filament increased the high frequency noise radiation by 2.5dB. In the underexpanded jet, the filament was determined to be most effective for any thickness greater than approximately 4% of the nozzle diameter and for lengths greater than three nozzle diameters. Temperature effects on the filament indicated that up to a temperature ratio of 1.82, which was the highest temperature ratio tested, the filament effectiveness increases with temperature.

Original languageEnglish (US)
Title of host publication39th Aerospace Sciences Meeting and Exhibit
StatePublished - 2001
Event39th Aerospace Sciences Meeting and Exhibit 2001 - Reno, NV, United States
Duration: Jan 8 2001Jan 11 2001

Other

Other39th Aerospace Sciences Meeting and Exhibit 2001
CountryUnited States
CityReno, NV
Period1/8/011/11/01

Fingerprint

jet aircraft noise
filaments
retarding
flow structure
Flow structure
temperature ratio
nozzles
Nozzles
shock
electromagnetic noise
turbulent mixing
acoustic emission
energy flow
Acoustic emissions
temperature effect
Thermal effects
Temperature
temperature effects
energy
Turbulence

ASJC Scopus subject areas

  • Space and Planetary Science
  • Aerospace Engineering

Cite this

Gutmark, E. J., Callender, B., Anderson, B. A., Bhat, T. R. S., & Wygnanski, I. J. (2001). Jet noise suppression using flexible filaments-review. In 39th Aerospace Sciences Meeting and Exhibit

Jet noise suppression using flexible filaments-review. / Gutmark, E. J.; Callender, B.; Anderson, B. A.; Bhat, T. R S; Wygnanski, Israel J.

39th Aerospace Sciences Meeting and Exhibit. 2001.

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

Gutmark, EJ, Callender, B, Anderson, BA, Bhat, TRS & Wygnanski, IJ 2001, Jet noise suppression using flexible filaments-review. in 39th Aerospace Sciences Meeting and Exhibit. 39th Aerospace Sciences Meeting and Exhibit 2001, Reno, NV, United States, 1/8/01.
Gutmark EJ, Callender B, Anderson BA, Bhat TRS, Wygnanski IJ. Jet noise suppression using flexible filaments-review. In 39th Aerospace Sciences Meeting and Exhibit. 2001
Gutmark, E. J. ; Callender, B. ; Anderson, B. A. ; Bhat, T. R S ; Wygnanski, Israel J. / Jet noise suppression using flexible filaments-review. 39th Aerospace Sciences Meeting and Exhibit. 2001.
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