Analyses of the mechanisms of amplitude modulation of aero-acoustic wind turbine sound

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Abstract

This paper explores the source mechanism which cause amplitude modulation of the emitted sound of a wind turbine at large distances from the turbine, named as other amplitude modulation. Measurements of the fluctuating surface pressure on a 2.3MW wind turbine showed a considerable variation over a blade revolution in the presence of angle of attack variations. If the blade undergoes transient stall, the variation of the surface pressure spectrum was enhanced and shifted to frequencies below 200Hz. The surface pressure spectra could be directly related to the emitted far eld sound. These ndings give further evidence that transient stall is a main mechanism to cause other amplitude modulation. Wind shear was identified as a critical condition to cause angle of attack variations. Dierent control strategies to mitigate other amplitude modulation were proposed.
Original languageEnglish
Title of host publicationProceedings of European Wind Energy Association Conference and Exhibition 2014
Number of pages12
PublisherEuropean Wind Energy Association (EWEA)
Publication date2014
Publication statusPublished - 2014
EventEuropean Wind Energy Conference & Exhibition 2014 - Fira de Barcelona Gran Via, Barcelona, Spain
Duration: 10 Mar 201413 Mar 2014
http://www.ewea.org/annual2014/

Conference

ConferenceEuropean Wind Energy Conference & Exhibition 2014
LocationFira de Barcelona Gran Via
CountrySpain
CityBarcelona
Period10/03/201413/03/2014
Internet address

Cite this

Fischer, A., Aagaard Madsen , H., Kragh, K. A., & Bertagnolio, F. (2014). Analyses of the mechanisms of amplitude modulation of aero-acoustic wind turbine sound. In Proceedings of European Wind Energy Association Conference and Exhibition 2014 European Wind Energy Association (EWEA).