INVESTIGATION OF WING SHIELDING EFFECTS ON CTOL ENGINE NOISE
A full scale engine wing shielding investigation was conducted at the Lewis Research Center using a 97,900-N (22,000 lb) thrust turbofan engine and a simulated wing section sized around a conventional-take-off type four-engine narrow body airplane. Sound data were obtained for the wing placed at seven positions in a plane parallel to the engine axis, and were compared to data obtained without the wing at both take off and approach power. In addition, the engine was operated with and without extensive acoustic treatment, including a sonic inlet in order to evaluate wing shielding effectiveness with a highly suppressed engine. The wing shielding effectiveness was also calibrated using a 3.8 cm diam air nozzle as a second source. Results indicated that even though about 10 dB broad band shielding was achieved, the equivalent flyover noise reduction was less than 3.0 EPNdB for most configurations.
- Presented at the 5th Annual Aeroacoustics Conference, Seattle, 12-14 March 1979, Sponsored by AIAA.
Department of the NavyThe Pentagon
Washington, DC United States 20350
- Bloomer, H E
- Publication Date: 1979
- Pagination: 34 p.
- TRT Terms: Aircraft noise; Damping (Engineering); Data collection; Engines; Noise; Noise barriers; Noise control; Static tests; Turbofan engines; Wings (Aircraft)
- Uncontrolled Terms: Aircraft engines; Noise reduction; Shielding
- Old TRIS Terms: Acoustic nozzles; Engine noise; Supersonic inlets; Wing design
- Subject Areas: Aviation; Environment; Vehicles and Equipment;
- Accession Number: 00197942
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: NASA-TM-79078
- Files: TRIS
- Created Date: Sep 15 1980 12:00AM