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Conference proceeding
Time-varying broadband noise of multirotor aircraft
Proceedings of Meetings on Acoustics, Vol.54(1)
Meeting of the Acoustical Society of America and the Canadian Acoustical Association, 186 (Ottawa, Canada, 05/13/2024–05/17/2024)
05/13/2024
Appears in Aviation Sustainability Center (ASCENT)
Abstract
Rotor broadband noise is typically analyzed over time scales encompassing multiple rotor periods. However, modulation of broadband noise levels with the blade passage frequency has been shown to be significant for human perception of wind turbine and helicopter noise. Time-varying broadband noise has not been extensively studied for aircraft with many rotors, such as unmanned aerial vehicles (UAVs) or advanced air mobility aircraft. In this work, significant broadband noise modulation was measured in flight and anechoic chamber tests of hexacopter UAVs. Envelope analysis showed that the modulation depth depends on the azimuthal phasing between rotors, demonstrating the potential for synchrophasing control to reduce broadband noise modulation. If rotors are not synchronized, as in typical flight, the phasing between rotors varies with time. This phase variation followed a uniform random distribution, resulting in modulation depth also varying randomly with time. The probability distribution of modulation depth was computed using offset copies of the modulation of a single rotor. These results contribute understanding to how the noise modulation of rotors sum together, demonstrating that broadband noise modulation is likely to be significant in flight.
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Details
- Title
- Time-varying broadband noise of multirotor aircraft
- Creators
- Ze Feng Gan - Department of Aerospace Engineering, The Pennsylvania State UniversityVitor Tumelero Valente - Pennsylvania State UniversityKenneth Steven Brentner - Pennsylvania State UniversityEric Greenwood - Department of Aerospace Engineering, The Pennsylvania State University
- Publication Details
- Proceedings of Meetings on Acoustics, Vol.54(1)
- Conference
- Meeting of the Acoustical Society of America and the Canadian Acoustical Association, 186 (Ottawa, Canada, 05/13/2024–05/17/2024)
- Academic Unit
- Aviation Sustainability Center (ASCENT); Noise
- Number of pages
- 12
- Grants
- 13-C-AJFE-PSU-099, Federal Aviation Administration (United States, Washington) - FAA
- Identifiers
- 99901177541001842
- Language
- English
- Resource Type
- Conference proceeding