SST Technology Follow-On Program-Phase 2, Noise Suppressor/Nozzle Development. Volume 2. Noise Technology
Final rept. on Task III
BOEING COMMERCIAL AIRPLANE CO SEATTLE WA
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Jet noise suppression, a major problem in the development of quiet airplane systems, has experienced a substantial technology advance as described in this report. Fundamental technology development has led to a better understanding of nozzle aerodynamics, noise generation and noise transmission processes. This report describes the results of a systematic, model-scale, multitube nozzle test program which generated far-field jet noise data, jet noise source location data, flow-profile data and jet noise data recorded in a wind tunnel to evaluate flight effects. The effects of various suppressor components are discussed in turn. They include unsuppressed nozzle, multitube nozzles, hardwall ejectors and acoustically-lined ejectors. The analysis covers the full range of acoustic parameters sound pressure levels, sound power levels, perceived noise levels, 13-octave-band spectra, and directivity effects. Analytical studies on jet noise reduction with simple gas shields are discussed, as are studies on the effects of jet noise-source locations and flow profiles on the acoustic lining effectiveness in ejectors. Selected jet noise and flow-profile backup data to this analysis can be found in Volume III of this document.
- Transport Aircraft
- Jet and Gas Turbine Engines