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Experimental evaluation of active and passive means of alleviating rotor impulsive noise in descent flight
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Janakiram, D. S. |
| Copyright Year | 1979 |
| Description | A controlled wind tunnel test program was conducted on a model 2.14 m (7 ft) diameter teetering rotor to determine the effectiveness of blade tips such as the Ogee tip and the TAMI (Tip Air Mass Injection) tip in reducing the impulsive noise due to blade-vortex interaction in descent flight. In addition, a full rectangular tip which has the same span as the Ogee tip and an effective rectangular tip which has the same lifting area as the Ogee tip were also considered. The tests were conducted at two advance ratios (0.125 and 0.14) with various descent rates ranging from steady level flight to about 6 m/sec (20 ft/sec). A comparison of the performance of different rotors showed that for the same tip Mach number and thrust, the Ogee tip rotor absorbed more power than the full rectangular tip rotor, while the TAMI tip rotor absorbed more power than the effective tip rotor. |
| File Size | 4225342 |
| Page Count | 90 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19800008579 |
| Archival Resource Key | ark:/13960/t0101zz0m |
| Language | English |
| Publisher Date | 1979-11-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Impulses Blade Tips Teetering Acoustic Measurement Noise Reduction Blade-vortex Interaction Flight Paths Aerodynamic Configurations Rotor Blades Turbomachinery Vortices Wind Tunnel Tests Blade Slap Noise Descent 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 |
