Ground reflection effects in measuring propeller aircraft flyover noise
Abstract
The influence of ground reflection on the maximum A-weighted aircraft noise level was investigated. Depending on propeller rotational speed and number of blades ground-reflection causes level differences of up to 3 dB(A). Since reflection corrections cannot successfully be applied to propeller noise signatures, alternative measuring arrangements such as microphones in close proximity to the ground were assessed. Depending on the positioning of the microphone in relation to an even, reverberant ground surface, or above ground plates, in the case of grass-covered surfaces, frequency ranges not affected by ground-reflection interferences are determined.
- Publication:
-
Ground reflection effects in measuring propeller aircraft flyover noise Transl. into ENGLISH of ""Interferenzwirkungen durch Bodenreflexion bei Fluglaermmessungen an Propellerflugzeugen'' DFVLR Rept. DFVLR-FB-81-28 DFVLR
- Pub Date:
- September 1982
- Bibcode:
- 1982grem.rept.....D
- Keywords:
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- Aircraft Noise;
- Ground Effect (Aerodynamics);
- Noise Measurement;
- Microphones;
- Propeller Drive;
- Reflected Waves;
- Acoustics