Aeroacoustic Assessment of Wind Plant Controls

Research output: NRELTechnical Report


The Aeroacoustic Assessment project aims to quantify changes in aeroacoustic noise generation by a utility scale wind turbine operating under imposed yaw offsets common for wake steering and wind plant control strategies. Active plant control utilizing wake deflection control strategies have been shown experimentally and computationally to reliably produce 1-2% of additional annual energy production (AEP) without significant changes in turbine structural loads, the potential impact on aeroacoustic emissions has yet to be quantified or completely understood. Yawed operation of a wind turbine changes the three-dimensional aerodynamic interaction between the rotor blades and the incoming atmospheric flow, leading to changes in noise generation. This work quantifies the extent to which active control induces additional aeroacoustic emissions from additional separation and other flow interaction dynamic effects. Given public concerns about wind turbine noise and the need for observational data required for regulators to establish noise restrictions, we must understand potential acoustic emissions resulting from active control prior to commercial deployment and the development of practical noise reduction methods and technology. The work outlined in this report details the new aeroacoustic measurement capability developed at NREL and its application to making full-field observations of noise from a utility-scale wind turbine. Preliminary noise modeling with the aeroacoustics module in OpenFAST helped to establish the design of the experiment, specifically targeting the noise observed at observers distributed around the DOE-owned GE 1.5 MW wind turbine. Low-frequency and infrasound measurement capability implemented in this project establish an operational baseline for the wind turbine, setting the stage for future control, rotor blade, and turbine design research. Noise generated by a wind turbine operating in yawed conditions is dominated by the turbulent inflow/leading edge interactions and by the trailing edge contributions. Modeled equivalent sound pressure levels and noise spectra match observed quantities for yaw offsets less than 20°, yielding a slight decrease in wind turbine noise, related to reduced tip speeds. At more aggressive yaw offsets, 25° as investigated in this work, the models suggest that wind turbine noise should increase overall. However, the observed noise at this yaw offset demonstrate reductions in wind turbine noise of up to 6 dB for particular wind speeds and observer locations. The experimental evidence in this study suggest that operating wind turbines under modern wind plant control strategies is unlikely to lead to additional noise emissions that could adversely impact wind plant operation. A quality-controlled data set containing the results of this work is hosted on the A2e Data Archive Portal (DAP). The data set includes sound pressure levels for all microphones, noise spectra, operational data from the wind turbine, and meteorological data from a met mast. These data are publicly available without charge and are intended to support the advancement of aeroacoustics research for wind energy. Data can be found at: Please cite this report if using the data for any research publications or reporting.
Original languageAmerican English
Number of pages98
StatePublished - 2021

NREL Publication Number

  • NREL/TP-5000-79664


  • aeroacoustics
  • wake steering
  • wind plant controls
  • wind turbine noise


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