Guan Yi-Jun, Ge Yong, Sun Hong-Xiang, Yuan Shou-Qi, Liu Xiao-Jun
Research Center of Fluid Machinery Engineering and Technology, School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
Key Laboratory of Modern Acoustics, National Laboratory of Solid State Microstructures, Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Micromachines (Basel). 2021 Dec 11;12(12):1544. doi: 10.3390/mi12121544.
In this work, a low-frequency, open, sound-insulation barrier, composed of a single layer of periodic subwavelength units (with a thickness of λ/28), is demonstrated both numerically and experimentally. Each unit was constructed using two identical, oppositely oriented Helmholtz resonators, which were composed of a central square cavity surrounded by a coiled channel. In the design of the open barrier, the distance between two adjacent units was twice the width of the unit, showing high-performance ventilation, and low-frequency sound insulation. A minimum transmittance of 0.06 could be observed around 121.5 Hz, which arose from both sound reflections and absorptions, created by the coupling of symmetric and asymmetric eigenmodes of the unit, and the absorbed sound energy propagating into the central cavity was greatly reduced by the viscous loss in the channel. Additionally, by introducing a multilayer open barrier, a broadband sound insulation was obtained, and the fractional bandwidth could reach approximately 0.19 with four layers. Finally, the application of the multilayer open barrier in designing a ventilated room was further discussed, and the results presented an omnidirectional, broadband, sound-insulation effect. The proposed open, sound-insulation barrier with the advantages of ultrathin thickness; omnidirectional, low-frequency sound insulation; broad bandwidth; and high-performance ventilation has great potential in architectural acoustics and noise control.
在这项工作中，通过数值模拟和实验展示了一种由单层周期性亚波长单元（厚度为λ/28）组成的低频开放式隔音屏障。每个单元由两个相同、方向相反的亥姆霍兹共振器构成，这些共振器由一个被螺旋形通道环绕的中央方形腔体组成。在开放式屏障的设计中，两个相邻单元之间的距离是单元宽度的两倍，展现出高性能通风和低频隔音效果。在121.5 Hz左右可观察到最小透过率为0.06，这是由单元对称和非对称本征模的耦合产生的声音反射和吸收共同导致的，并且传入中央腔体的吸收声能因通道中的粘性损耗而大幅降低。此外，通过引入多层开放式屏障，获得了宽带隔音效果，四层时分数带宽可达约0.19。最后，进一步讨论了多层开放式屏障在通风房间设计中的应用，结果呈现出全方位、宽带的隔音效果。所提出的开放式隔音屏障具有超薄厚度、全方位低频隔音、宽带宽和高性能通风等优点，在建筑声学和噪声控制方面具有巨大潜力。
