Experimental characterization of the acoustic coupling between a sonic black hole and a resonant cavity

Sonic black holes (SBHs) are waveguides designed to slow down incident sound waves and dissipate their energy, leading to near-perfect absorption. While numerous studies have focused on the modeling, experimental characterization, design optimization, and comprehension of the internal wave dynamics of isolated SBHs, their interaction with other acoustic systems has received little attention. In this context, SBHs have previously been investigated numerically as a means of reducing noise inside resonant cavities. This work aims to experimentally assess the coupled cavity–SBH problem and evaluate the accuracy of the numerical patch transfer function (PTF) method in describing this interaction. To this end, experimental setups for the SBH, the resonant cavity, and the fully coupled system are presented. The PTF framework is briefly reviewed, and numerical strategies based on the finite element method (FEM) and modal expansion formulations are developed for the SBH and cavity subsystems, respectively. The response of the coupled system is then reconstructed using the PTF approach and compared against experimental measurements. Different SBH configurations are investigated, including variations in their location on the top surface of the cavity and the inclusion of melamine filling between SBH rings. The resulting mean quadratic pressure inside the cavity is then analyzed.