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Helicopter rotor rotational noise predictions based on measured high-frequency blade loads
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Ramakrishnan, R. Hosier, R. N. |
| Copyright Year | 1974 |
| Description | In tests conducted at the Langley helicopter rotor test facility, simultaneous measurements of up to 200 harmonics of the fluctuating aerodynamic blade surface pressures and far-field radiated noise were made on a full-scale nontranslating rotor system. After their characteristics were determined, the measured blade surface pressures were converted to loading coefficients and used in an existing theory to predict the far-field rotational noise. A comparison of the calculated and measured noise shows generally good agreement up to 300 to 600 Hz, depending on the discreteness of the loading spectrum. Specific attention is given to the effects of the blade loading coefficients, chordwise loading distributions, blade loading phases, and observer azimuthal position on the calculations. |
| File Size | 4930466 |
| Page Count | 87 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19750004831 |
| Archival Resource Key | ark:/13960/t3gx93257 |
| Language | English |
| Publisher Date | 1974-12-01 |
| Access Restriction | Open |
| Subject Keyword | Aerodynamics Noise Propagation Acoustic Properties Stress Cycles Cyclic Loads Performance Prediction Pressure Distribution Aerodynamic Noise Rotor Aerodynamics Rotary Wings Aerodynamic Loads Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
