Fabry–Pérot resonances of acoustic waves in disordered slabs

The reflection and transmission of acoustic waves by slabs composed of parallel cylinders randomly distributed in a fluid are investigated theoretically, numerically, and experimentally. Measurements of the reflection and transmission coefficients are carried out on samples of concentrations ϕ=20% and ϕ=30% of steel rods immersed in water. These results experimentally highlight the existence of Fabry–Pérot resonances in disordered slabs. Moreover, the experiments are in quantitative agreement with numerical simulations and a modeling based on multiple scattering theory.