Acoustic Black Hole Pillars for Noise Reduction in a Resonant Cavity Filled with Heavy Fluid

This paper investigates the reduction of sound radiation by beams with attached acoustic black hole (ABH) pillars in resonant cavities filled with heavy fluids (e.g., water) and light fluids (e.g., air). Fluid–structure interaction systems, particularly those involving heavy fluids, present significant challenges for vibration control and noise reduction. While traditional passive control methods often fail to provide effective suppression across a broad frequency range, ABHs have shown considerable potential in mitigating both vibration and acoustic radiation. The paper analyzes the underlying mechanisms driving the behavior of the coupled system, focusing on the effects of local resonances and the acoustic impedance mismatch between the structure and surrounding fluid. The problem is examined using a displacement/acoustic displacement formulation, which is validated through comparison with finite element method simulations. The results suggest that ABH pillars offer a promising solution for noise control in submerged structures.