This work revisits an indirect characterization method that exploits visco-inertial and thermal frequency response functions to estimate the macroscopic parameters of fibrous media Panneton and Olny, J. Acoust. Soc. Am. 119, 2027-2040 (2006); Olny and Panneton, J. Acoust. Soc. Am. 123, 814-824 (2008). In practice, this method faces major challenges for highly resistive materials because the transition frequencies fall outside the measurable range of the standing-wave tube. To overcome this limitation, an alternative approach combining the equivalent characteristic-length relation derived from ultrasound measurements with a Kozeny-Carman-type relation is proposed. The methodology and its validation on resistive felts demonstrate improved estimation of viscous and thermal characteristic lengths from measurable parameters.
Tran et al. (Sun,) studied this question.