The noise generated by wind turbines is a critical issue that impacts both operational efficiency and public health, necessitating a comprehensive investigation into its sources and propagation. This study investigates the near-wake noise of an S-airfoil horizontal-axis wind turbine using statistically optimized near-field acoustic holography (SONAH) with a 60-channel rotating microphone array in an open-jet wind tunnel. The results show that the noise in the wake is predominantly caused by the rotation of the rotor. The position of the highest sound pressure level concentration is at 0.78R of the blade under different operating conditions within the rotor’s rotation plane. The sound pressure level radiates outward in a spiral pattern across eleven identified sections, progressively decreasing with distance. The most significant attenuation occurs between 0.04 m and 0.06 m from the rotating surface. This study provides foundational insights into the near-field acoustic characteristics of wind turbines, serving as a valuable reference for noise reduction strategies and environmental impact assessments in wind energy projects.
Wang et al. (Fri,) studied this question.