Broadband ventilated sound insulation in a highly sparse acoustic meta-insulator array
Siyuan Gao, Yifan Zhu, Zihao Su, Haohan Zeng, Hui Zhang
Abstract
Ventilated acoustic insulators can block sound whereas simultaneously allowing airflow, which has potential applications for noise control in ventilation structures. In this paper, we propose a highly sparse acoustic meta-insulator array consisting of multiple tunable units. The meta-insulator unit with a minimum deep subwavelength thickness of $0.064\ensuremath{\lambda}$ has openings on two sides and a joint capacity. We propose an analytical model to reveal its physical mechanism. We numerically and experimentally demonstrate the highly sparse acoustic meta-insulator array with 20 units capable of ventilated sound insulation with a broad bandwidth of over 1 octave (from approximately 880 to 1915 Hz), a high sparsity of about 70%, and sound attenuation of more than 17 dB suitable for both near-field and far-field sound sources. Our designs may offer alternative solutions to ventilation noise control issues on various practical occasions.