Nonlinear sound absorption of bidirectional rough microperforated plates under high-intensity sound fields

Abstract The acoustic performance of bidirectional rough microperforated plates under high-intensity acoustic excitation is systematically examined through integrated theoretical modeling, numerical simulations, and experimental validation. Considering the nonlinear effect of high-intensity acoustic excitation, a theoretical modeling of the acoustic performance of the bidirectional rough microperforated plate at high-intensity acoustic excitation is established. Moreover, the numerical model is developed using the nonlinear N-S equations, which takes into account the compressibility of the fluid, for calculating the nonlinear acoustic performance and sound field distribution. Findings indicate a progressive rise in acoustic resistance and a marginal reduction in acoustic reactance with increasing incident sound pressure levels, resulting in an upward shift of the peak absorption frequency. The high particle velocity induced by high sound pressure levels (SPLs) drives the flow field inside the perforations to transition from stable laminar flow to an unstable state, accompanied by the formation of strong flow separation, recirculation, and nonlinear vortical structures at the perforation outlet—these structures enhance viscous and thermal energy dissipation. Impedance tube testing was employed to evaluate the sound absorption performance of a 3D-printed specimen, with the experimental data demonstrating favorable consistency with the theoretical predictions. This work demonstrates that the bidirectional rough microperforated plate exhibits effective sound absorption capabilities under high-intensity acoustic excitation conditions.