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Description
Low-frequency noise remains difficult to mitigate in urban environments because conventional absorbers require large thicknesses or compromise structural performance. This study investigates a Tesla-valve-inspired acoustic metamaterial embedded within high-strength cementitious composites and evaluates how geometric parameters control acoustic behavior. A parametric investigation was conducted to examine the influence of coiling angle, channel length, valve count, and Helmholtz neck diameter on sound absorption in the 200–2500 Hz frequency range. Numerical simulations were performed using the thermoviscous acoustics interface in COMSOL Multiphysics, combined with the Johnson–Champoux–Allard (JCA) model, to capture viscous and thermal dissipation within the metamaterial channels and the surrounding mortar matrix. The results indicate that increasing the coiling angle increases tortuosity and the effective acoustic path length, shifting the resonance frequency from approximately 830 Hz to 420 Hz. Channel length enables near-linear tuning of the resonance position, whereas increasing the valve count introduces multiple standing-wave modes that broaden the absorption bandwidth. The Helmholtz neck diameter further tunes mid- and high-frequency absorption behavior. Experimental measurements using an in-situ PU-probe method confirm the simulation trends, with peak absorption coefficients reaching approximately 0.90–0.95. The findings provide practical design guidelines for integrating load-bearing cementitious acoustic metamaterials for tunable low-frequency sound control.