The Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administration Region.
J Acoust Soc Am. 2013 Sep;134(3):1990-2003. doi: 10.1121/1.4817887.
With ever-increasing land traffic, abatement of traffic noise using noise barriers remains significant, yet it is a challenging task due to spatial competition with other infrastructure. In this study, a deep insight into the diffraction characteristics of acoustic fields near noise barriers of various geometries and surface conditions was achieved using numerical simulations. A T-shaped passive noise barrier with acoustically soft upper surfaces was demonstrated to outperform other candidates in a middle- or high-frequency range. Based on attributes of the acoustic field diffracted by T-shaped barriers, an active control strategy was developed to revamp the T-shaped barrier, in which a filtered minimax algorithm was established to drive the secondary sound sources. This algorithm resulted in more uniformly distributed residual sound fields than a filtered-X least mean square algorithm. Performance of the actively controlled barrier was evaluated at different positions and spacings of secondary sound sources and error sensors, leading to a series of optimal criteria for the design of active noise barriers. A prototype was fabricated and validated experimentally, manifesting particular effectiveness in insulating low-frequency noise, supplementing well the capacity of a passive T-shaped barrier which is effective in the middle- or high-frequency range.
随着土地交通的不断增加，使用隔音墙来减少交通噪音仍然非常重要，但由于与其他基础设施的空间竞争，这是一项具有挑战性的任务。在这项研究中，通过数值模拟深入了解了各种几何形状和表面条件的隔音墙附近声场的衍射特性。研究表明，具有声学软上表面的 T 形无源隔音墙在中高频范围内优于其他候选者。基于 T 形屏障衍射声场的特性，开发了一种主动控制策略来改进 T 形屏障，其中建立了一个滤波极大极小算法来驱动次级声源。与滤波-X 最小均方算法相比，该算法导致残余声场分布更加均匀。在不同位置和次级声源和误差传感器的间距下评估了主动控制屏障的性能，得出了一系列主动噪声屏障设计的最佳准则。制作了一个原型并进行了实验验证，该原型在隔离低频噪声方面表现出了特殊的效果，很好地补充了在中高频范围内有效的无源 T 形屏障的能力。
