Tonal noise measurements of a small propeller in an open and closed test facility
Tonal noise measurements of a small propeller in an open and closed test facility
Date
2022
Authors
Bokhorst, E. van
Brouwer, H.H.
Journal Title
Journal ISSN
Volume Title
Publisher
AIAA
Abstract
In this paper experiments and simulations on tonal noise of a small propeller are described.
Experiments were carried out in the open-jet and closed test section configuration of the Aeroacoustic
Wind Tunnel at NLR Marknesse. From previous investigations it has been found that when acoustic
beamforming techniques are applied, the acoustic source is not located at the propeller blade itself.
Therefore a new propeller steering function for acoustic beamforming is introduced which
incorporates the operating conditions of the propeller. With the new steering function it is more easy
to identify the source location however the large depth of field prevents the possibility to use three
dimensional beamforming. Instead, to define the y-coordinate of the virtual source location the openjet
simulations are used. The final comparison between the open-jet and closed test section
measurements shows that the resonances in the tunnel and reflections influence the sound pressure
levels significantly. More work is needed to fully understand these effects.
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Citation
2022 SciTech Forum, San Diego, USA