Abstract:

The National Wind Technology Center (NWTC) has been involved in wind turbine acoustics since the 1980s. The areas of work include standards development, measurement and analysis, prediction code development, and acoustic arrays. Most measurements are conducted to the IEC 61400‐11, a standard specifically for acoustic measurements of wind turbines. The NWTC is involved in the development of this standard. The standard results in reports of overall levels as well as tonality. The NWTC has also developed a semiempirical acoustic noise prediction code for wind turbines. Validation of this code with test data (both wind tunnel and field measurements) shows reasonable prediction accuracy for both airfoil self noise and turbulent inflow noise. Lastly, to assist with wind turbine noise reduction and to identify the loudest components an acoustic array was developed to better locate noise on wind turbines. This paper will describe the NWTC’s past and current activities in wind turbine acoustics including test methods and results.