Prediction of outdoor ground effect
Year: 2025
Type: article
Abstract: A classification of outdoor ground surfaces for calculating the attenuation due to destructive interference between direct and ground-reflected sound is proposed which uses a physically admissible ground impedance model with parameters of porosity, flow resistivity, and, for some ground surfaces, layer depth. This impedance model is shown to enable good fits to short range level difference measurements over a wide range of ground surfaces. Ranges of parameter values are suggested in each class to allow for variations in soil depth profiles, moisture content and surface roughness. Also, methods are proposed to account for mean ground roughness heights of less than 0.1 m and for waves on a water surface. The influence of atmospheric turbulence on ground effect is included through a coherence factor which includes both wind- and temperature-induced fluctuations and assumes a Kolmogorov turbulence spectrum. To account for changes in impedance along the propagation path, a Fresnel zone method is proposed which weights pressures squared since this method has been shown to compare better with 2D Boundary Element Method predictions than a method that weights excess attenuation.
Source: Applied Acoustics
Authors: Keith Attenborough, Shahram Taherzadeh
Institution: The Open University
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,820
OpenAlex ID: W4414395028