Sound Absorption Modeling in Porous Materials: A Critical Review of Empirical, Equivalent-Fluid, Poroelastic, Resonant, and Numerical Methods

This paper provides a comprehensive overview of the main empirical, equivalent-fluid, poroelastic, resonant, and numerical models used to describe sound absorption in porous materials. Each model is described in detail with regard to its theoretical basis, governing equations, and key physical parameters. Special attention is devoted to the assumptions underlying each model, such as whether the frame is rigid or flexible, the applicable frequency range, and the types of porous media they most accurately represent. The advantages and limitations of the different approaches are critically assessed in terms of prediction accuracy, computational complexity, physical interpretability, and experimental requirements. In addition, this paper summarizes and critically discusses published model–experiment comparisons for representative porous and resonant acoustic materials. These comparisons highlight the strengths and weaknesses of different modeling strategies in various acoustic applications and provide guidance for selecting the most suitable model according to the material properties and target frequency range. The review shows that equivalent-fluid models generally provide the best compromise between prediction accuracy and computational efficiency for rigid-frame porous materials, whereas Biot-type poroelastic models are more suitable when frame motion cannot be neglected.