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Ultra-high bypass ratio jet noise
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Low, John K. C. |
| Copyright Year | 1994 |
| Description | The jet noise from a 1/15 scale model of a Pratt and Whitney Advanced Ducted Propulsor (ADP) was measured in the United Technology Research Center anechoic research tunnel (ART) under a range of operating conditions. Conditions were chosen to match engine operating conditions. Data were obtained at static conditions and at wind tunnel Mach numbers of 0.2, 0.27, and 0.35 to simulate inflight effects on jet noise. Due to a temperature dependence of the secondary nozzle area, the model nozzle secondary to primary area ratio varied from 7.12 at 100 percent thrust to 7.39 at 30 percent thrust. The bypass ratio varied from 10.2 to 11.8 respectively. Comparison of the data with predictions using the current Society of Automotive Engineers (SAE) Jet Noise Prediction Method showed that the current prediction method overpredicted the ADP jet noise by 6 decibels. The data suggest that a simple method of subtracting 6 decibels from the SAE Coaxial Jet Noise Prediction for the merged and secondary flow source components would result in good agreement between predicted and measured levels. The simulated jet noise flight effects with wind tunnel Mach numbers up to 0.35 produced jet noise inflight noise reductions up to 12 decibels. The reductions in jet noise levels were across the entire jet noise spectra, suggesting that the inflight effects affected all source noise components. |
| File Size | 31574258 |
| Page Count | 64 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19950008196 |
| Archival Resource Key | ark:/13960/t5hb4283n |
| Language | English |
| Publisher Date | 1994-10-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Temperature Dependence Subsonic Speed Jet Aircraft Noise Bypass Ratio Noise Reduction Noise Spectra Nozzle Geometry Exhaust Nozzles Noise Intensity Noise Prediction Aircraft Wind Tunnel Tests Turbofan Engines Prediction Analysis Techniques Aeroacoustics Thrust Mach Number Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
