A spectral-band estimation method of ground acoustic impedance for wind turbine sound propagation

Chao Ma
College of Electrical, Energy and Power Engineering, Yangzhou University, Yangzhou 225127, China; Wuxi Smart Auto-Control Engineering Co., Ltd., Wuxi 214112, China
Weifeng Yan
CGC Jiangsu Test & Certification Limited, Yancheng 224100, China
Shuyu Shen
College of Electrical, Energy and Power Engineering, Yangzhou University, Yangzhou 225127, China
Wenzhong Shen
College of Electrical, Energy and Power Engineering, Yangzhou University, Yangzhou 225127, China; College of Renewable Energy, Hohai University, Changzhou 213200, China
Chang Xu
College of Renewable Energy, Hohai University, Changzhou 213200, China

Article ID: 4624

Keywords: wind turbine sound propagation; ground acoustic impedance; acoustic measurement; spectral-band method; flow resistivity

Abstract

Accurate characterization of ground acoustic impedance is essential for reliable prediction of wind turbine sound propagation over natural and agricultural surfaces. In conventional indirect measurements, a loudspeaker and two microphones at different heights are used to estimate an equivalent flow resistivity by fitting the measured sound pressure level (SPL) differences with those calculated from an image-source propagation model and an acoustic impedance model. Because this fitting is generally carried out over a broad frequency range, the conventional approach is referred to here as the global-band method. However, a single full-band flow resistivity may not represent the frequency-dependent ground response with sufficient accuracy. To improve the spectral representation of the ground boundary condition, this paper proposes a spectral-band method for determining the ground impedance in individual 1/3-octave frequency bands. The method is intended to provide more accurate impedance inputs for wind turbine sound propagation models. The results show that the spectral-band method more accurately captures the frequency-dependent behavior of the effective flow resistivity and ground impedance, significantly reducing the discrepancy between calculated and measured SPL differences. In addition, an empirical formula is established to describe the relationship between the flow resistivity obtained using the global-band method and that obtained using the spectral-band method, so that the ground impedance can be more conveniently specified for simulations at individual frequency bands.

Published

2026-08-26

How to Cite

Ma, C., Yan, W., Shen, S., Shen, W., & Xu, C. (2026). A spectral-band estimation method of ground acoustic impedance for wind turbine sound propagation. Sound & Vibration, 60(6). https://doi.org/10.59400/sv4624

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Issue

Vol. 60 No. 6 (2026): In Progress

Section

Article

This work is licensed under a Creative Commons Attribution 4.0 International License.

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