An Inverse Method Based on Impedance Tubes for Determining Low-Frequency Non-acoustic Parameters of Rigid Porous Media

BackgroundThe background of the study involves the characterization of porous media using an innovative acoustic method. The researchers focus on determining specific parameters related to wave propagation in porous materials. They utilize the equivalent fluid model, a special case of Biot's theory, to understand how sound waves travel through these materials.PurposeThe purpose of the study is to introduce a novel acoustic method for characterizing porous media and determining four important low-frequency non-acoustic parameters. These parameters are viscous permeability, thermal permeability, Norris' inertial factor (viscous tortuosity), and Lafarge's thermal tortuosity. The researchers aim to achieve this characterization by utilizing impedance measurements, numerical solutions for the inverse problem, and experimental data from polyurethane foam samples.ResultsThe researchers successfully developed and applied the innovative acoustic method to estimate the aforementioned parameters for polyurethane foam samples. The method's accuracy is demonstrated by showing consistent results with direct measurement techniques. Additionally, the absorption coefficients calculated through simulations closely match the experimental data. Importantly, the study's key contribution is its simultaneous measurement of various parameters solely based on low-frequency experimental absorption coefficients. This approach offers a cost-effective and promising alternative to existing methods for characterizing porous media.ConclusionThe study presents a new acoustic method that effectively characterizes porous media and determines key parameters related to wave propagation. This method has been applied to polyurethane foam samples and provides accurate results, offering a cost-effective alternative for characterizing porous materials with potential applications in noise control, acoustic insulation, and environmental acoustics.

Automated summary

This study presents an innovative acoustic method for characterizing porous media and determining key parameters related to wave propagation. The researchers successfully developed and applied this method to estimate parameters for polyurethane foam samples, demonstrating its accuracy and potential applications in noise control and acoustic insulation.