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| Acoustics of porous media: from microscopic geometrical structures to macroscopic sound absorption performances |
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Abstract Conventional porous media such as fibers and foams have good sound absorption characteristics at mid and high frequencies. They are commonly used in fields of construction, automotive, aviation, industry and environmental noise control. The complex microstructures and various macroscopic sound absorption properties of porous media have been highly concerned and studied by researchers. These studies are often based on the first principles in acoustics, start from the sound absorbing mechanism, and explore scientific laws in microscopic and macroscopic levels in order to discover or create novel structures with better sound absorption performances. This paper combs the studies from microscopic geometrical structure analyses to macroscopic sound absorption characteristics, and exhibits related achievements and orientations in the past one or two decades. First, the microstructure characteristics, visualization pathway, and geometric parameters are introduced. Secondly, the history from establishment to improvement of acoustic models is reviewed. Thirdly, physical quantities that determine the acoustic performance are summarized, and their physical meanings are discussed. Then, the theoretical calculations, numerical simulations, and experimental measurements for the macroscopic properties are described and compared. Finally, relevant empirical fitting formulas that associate micro-macro relations between two scales are listed aiming to analyze factors that affect the acoustic performance. The prospects are discussed at last.
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Received: 08 October 2021
Published: 12 October 2022
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Corresponding Authors:
Liang Xia
E-mail: xialiang@hust.edu.cn
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2022, Vol. 43 
