Location of aerodynamic noise sources from a 200 kW vertical-axis wind turbine. (21st July 2017)

• Record Type: Journal Article
• Authors: Ottermo, Fredric; Möllerström, Erik; Nordborg, Anders; Hylander, Jonny; Bernhoff, Hans
• Is Part Of: Journal of sound and vibration. Volume 400(2017)
• Page Start: 154
• Page End: 166
• Publication Date: 2017-07-21
• Subjects: Vertical-axis wind turbine -- H-rotor -- Noise -- Microphone array -- Beamforming; Sound -- Periodicals; Vibration -- Periodicals; Son -- Périodiques; Vibration -- Périodiques; Sound; Vibration; Periodicals; Electronic journals; 620.205
• DOI: 10.1016/j.jsv.2017.03.033
• Languages: English
• ISSNs: 0022-460X

Abstract

Abstract: Noise levels emitted from a 200 kW H-rotor vertical-axis wind turbine have been measured using a microphone array at four different positions, each at a hub-height distance from the tower. The microphone array, comprising 48 microphones in a spiral pattern, allows for directional mapping of the noise sources in the range of 500 Hz to 4 kHz. The produced images indicate that most of the noise is generated in a narrow azimuth-angle range, compatible with the location where increased turbulence is known to be present in the flow, as a result of the previous passage of a blade and its support arms. It is also shown that a semi-empirical model for inflow-turbulence noise seems to produce noise levels of the correct order of magnitude, based on the amount of turbulence that could be expected from power extraction considerations.