Characterizing high-frequency wave interaction in rigid porous bilayer materials: Insights from acoustic parameter sensitivity analysis

Abstract

This study aims to investigate the sensitivity of high-frequency acoustic parameters in rigid air-saturated porous bilayer materials using the equivalent fluid theory. The interaction between the fluid and solid phases of the porous medium incorporates visco-inertial and thermal exchange, characterized by two functions: the dynamic tortuosity α(ω) proposed by Johnson etal. and the dynamic compressibility β(ω) proposed by Allard, refined by Sadouki for the low-frequency domain of ultrasound. Various parameters, including porosity, tortuosity, viscous characteristic length, thermal characteristic length, as well as viscous and thermal shape factors, are examined in this study. A 10% variation in these parameters is considered to assess their impact on the amplitudes of transmitted waves. The findings of this study contribute to a deeper understanding of high-frequency wave behavior in porous bilayer materials. The investigation sheds light on the sensitivity of the parameters and provides valuable insights for the design and optimization of such materials in engineering, technology, and applied sciences.