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Forward velocity effects on fan noise and the suppression characteristics of advanced inlets as measured in the nasa-ames 40 by 80 foot wind tunnel
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Moore, M. T. |
| Copyright Year | 1980 |
| Description | Forward velocity effects on the forward radiated fan noise and on the suppression characteristics of three advanced inlets relative to a baseline cylindrical inlet were measured in the NASA Ames Research Center 40 x 80 foot Wind Tunnel. A modified JT15D turbofan engine in a quiet nacelle was the source of fan noise; the advanced inlets were a Conventional Takeoff/Landing (CTOL) hybrid inlet, a Short Takeoff/Landing (STOL) hybrid inlet, and a treated deflector inlet. Also measured were the static to flight effects on the fan noise of canting the baseline inlet 4 deg downward to simulate typical wing mounted turbofan engines. The CTOL hybrid inlet suppressed the high tip speed fan noise as much as 18 PNdB on a 61 m (200 ft) sideline scaled to a CF6 size engine while the STOL hybrid inlet suppressed the low tip speed fan noise as much as 13 PNdB on a 61 m (200 ft) sideline scaled to a OCSEE size engine. The deflector inlet suppressed the high tip speed fan noise as much as 13 PNdB at 61 m (200 ft) overhead scaled to a CF6 size engine. No significant changes in fan noise suppression for the CTOL and STOL hybrid inlets occurred for forward velocity changes above 21 m/s (68 ft/s) or for angle of attack changes up to 15 deg. However, changes in both forward velocity and angle of attack changed the deflector inlet noise unpredictably due to the asymmetry of the inlet flow field into the fan. |
| File Size | 11767100 |
| Page Count | 161 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19820022154 |
| Archival Resource Key | ark:/13960/t55f3mz86 |
| Language | English |
| Publisher Date | 1980-05-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Acoustic Properties Engine Noise Engine Inlets Wind Tunnel Tests Data Processing Turbofan Engines Noise Measurement Aerodynamic Characteristics Static Tests Tip Speed 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 |
