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Correlation of helicopter impulsive noise from blade-vortex interaction with rotor mean inflow
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Connor, Andrew B. Martin, R. M. |
| Copyright Year | 1987 |
| Description | Data from a test made in the Langley 4 x 7 Meter Tunnel were parametrically studied with respect to the occurrence of blade-vortex interaction (BVI) as a function of tunnel speed and rotor angle of attack. Three microphones on the tunnel centerline forward of the model and one microphone forward and 45 degrees to the right provided the data. The rotor model was tested with a set of high-twist blades (-10 degrees) and a set of low-twist blades (-5 degrees) over the midspeed range (50 to 80 knots) at angles of attack ranging from -6 degrees (shallow climb) to 10 degrees (steep descent). The data from all four microphones indicated that the most probable time of occurrence of BVI is when the rotor descent is approximately equal to the rotor mean inflow velocity. However, some of the data showed no conclusive relationship to the mean inflow velocity. |
| File Size | 8274788 |
| Page Count | 23 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19870008966 |
| Archival Resource Key | ark:/13960/t3sv2gj22 |
| Language | English |
| Publisher Date | 1987-03-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Rotor Blades Turbomachinery Helicopters Vortices Flow Distribution Wind Tunnel Tests Blade-vortex Interaction Flow Velocity Angle of Attack Blade Slap Noise Microphones 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 |
