Interaction of near-wall bubble arrays with acoustic waves induced by an oscillating rigid wall

The interaction of near-wall bubbles with acoustic waves generated by an oscillating rigid wall is studied using two-dimensional Euler equations, together with a pressure-velocity equilibrium model in each cell. Case studies are first performed for a single bubble and a 1×4 array over a frequency range of 0.75∼162.5 kHz. Two major resonance phenomena are observed: Minnaert and quarter-wave gap resonances due to the gap between the wall and the bubble(s). The bubbles are shown to absorb a substantial portion of acoustic energy near the Minnaert frequency. Quarter-wave gap resonances are marked by pressure maxima at the wall and within inter-bubble gaps, whereas bubble-center responses remain weak. Analysis of the pressure ratio indicates acoustic attenuation is very strong at Minnaert resonances and in the short-wave regime, but much weaker at quarter-wave gap resonances. Bubble arrays enhance attenuation compared with a single bubble, due to inter-bubble coupling and multiple scattering. The investigation is further extended to 5×4, 10×2, and 20×1 bubble arrays at the resonant frequencies, illustrating how different arrangements modify the collective response. The results provide physical insight into the interaction of near-wall bubbles with underwater acoustic waves and are potentially beneficial to underwater noise mitigation and bubble-based acoustic-control systems.