Noise levels from a VSTOL aircraft measured at ground level and at 1.2 m above the ground
Abstract
During a series of aircraft flight tests using a British Aerospace Sea Harrier (FRS Mk1) noise measurements were obtained using microphones close to the ground plane and at a height of 1.2 m. Substantial differences from ground level to 1.2 m were observed, in measurements of perceived noise level and effective perceived noise level. The differences were found to be dependent on ground cover and flight maneuver and for a microphone located 1.2 m above a grass surface a dependence on precise microphone positioning was observed. The ground-plane microphones produced noise levels which closely approximated pressure-doubled values. A procedure for correcting 1/3 octave band sound pressure levels measured 1.2 m above the ground, to obtain pressure-doubled levels is examined. It is concluded that to avoid significant variations in measured noise levels, measurements should be made using a ground-plane microphone arrangement.
- Publication:
-
Unknown
- Pub Date:
- October 1989
- Bibcode:
- 1989nlva.rept.....P
- Keywords:
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- Effective Perceived Noise Levels;
- Jet Aircraft Noise;
- Noise Intensity;
- Noise Measurement;
- Sound Pressure;
- Flight Tests;
- Microphones;
- Position (Location);
- Pressure Dependence;
- V/Stol Aircraft;
- Acoustics