Discussion of Infrasound Measurements of a Wind Turbine

Wind turbines in operation produce infrasound due to the rotor blade passing the tower while interacting with the fluid. This results in a directly measurable periodic pressure fluctuation. At the same time, a measured stochastic signal is caused by the wind itself. A frequency-domain investigation becomes possible after Fourier transformation with the evaluation of the power spectrum and the power spectral density, respectively. Results confirm that the infrasound signals of an investigated wind turbine with an electrical power of 660 kW are, at a distance of 200 m, clearly below the threshold of perception, cf. Baumgart et al. in JSV 2021, 116310. The wind itself contributes the most to the infrasound signal. In this work, the authors discuss ways for analyzing infrasound measurements and the specific application and classification of the subsequent spectral analysis. This way, a consistent framework provides a sound scientific basis for the classification of infrasound by, for example, legal authorities.