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Description
A 1D finite-difference time-domain (FDTD) simulation is proposed for the acoustic characterisation of multilayer textile absorbers. Dissipative mechanisms are derived directly from five measurable microstructural parameters per layer, open porosity, airflow resistivity, tortuosity, and viscous and thermal characteristic lengths, through the Johnson–Champoux–Allard (JCA) equivalent-fluid model. Frequency-dependent viscous and thermal losses are introduced into the time-domain solver via two Auxiliary Differential Equations (ADE). Reflection, transmission, and absorption coefficients are extracted. The extracted absorption spectrum is compared against the Transfer Matrix Method (TMM),and the two results are in close agreement across the frequency band of interest.