Artificial porous crystal for broadband attenuation of surface gravity waves

While hydrodynamic metamaterials offer innovative strategies for manipulating surface gravity waves, their practical attenuation efficacy is often constrained by narrow bandwidths. Here, we propose an artificial porous crystal composed of periodic perforated plates engineered to transform this narrow Bragg-type response into broadband dissipative attenuation. By combining the linear potential flow theory with Darcy's law, we analytically map the band structure and scattering characteristics of this macroscopic lattice, and the modified complex dispersion relations reveal its broadband wave-decay capabilities. These theoretical predictions are validated using wave-flume experiments. Furthermore, high-fidelity particle image velocimetry (PIV) explicitly captures the underlying micromechanics, demonstrating that the broadband energy dissipation is governed by distributed, pore-induced vortex interference. Our findings advance the fundamental understanding of wave–structure interactions and present a scalable, passive architecture for macro-scale wave control.