He Yu, Zhong Siyang, Huang Xun
Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong Special Administrative Region.
State Key Laboratory of Turbulence and Complex Systems, Aeronautics and Astronautics, College of Engineering, Peking University, Beijing, China.
J Acoust Soc Am. 2019 Jul;146(1):41. doi: 10.1121/1.5115046.
Most of the acoustic cloak designs are based on the stationary medium, which, however, may be inaccurate in many practical applications with non-uniform flows. The optimization of the acoustic cloaking performance was described as an active noise control problem, and the theoretical model by Huang, Zhong, and Stalnov [J. Acoust. Soc. Am. 135(5), 2571-2580 (2014b)] was employed for the quick evaluation of the sound scattering. In this work, extensions are made to address the unsolved but essential issues in the model. First, the impact of the discontinuities at the interface between the cloak and surrounding fluids is investigated. Second, the high-order Born's approximation is employed to solve the sound governing equation, which can quickly improve the prediction accuracy. Finally, the optimized cloaking strategy is applied to airfoils in turbulent flows to demonstrate the capability of the proposed modelling for cases of practical importance. Also, it is found that the performance of the optimized cloak is insensitive to the frequency of the incident wave. The promising results suggest that an optimized cloaking design can effectively suppress the sound scattering, providing the confidence with the mathematical framework for the potential aeronautics and marine applications.
大多数声学隐身衣设计基于静止介质，然而，在许多具有非均匀流的实际应用中，这可能并不准确。声学隐身性能的优化被描述为一个有源噪声控制问题，并且采用了Huang、Zhong和Stalnov [《美国声学学会杂志》135(5)，2571 - 2580(2014b)] 的理论模型来快速评估声散射。在这项工作中，进行了扩展以解决该模型中未解决但至关重要的问题。首先，研究了隐身衣与周围流体界面处的不连续性的影响。其次，采用高阶玻恩近似来求解声控制方程，这可以快速提高预测精度。最后，将优化的隐身策略应用于湍流中的翼型，以证明所提出的建模对于实际重要情况的能力。此外，发现优化后的隐身衣性能对入射波频率不敏感。这些有前景的结果表明，优化的隐身设计可以有效抑制声散射，为潜在的航空和海洋应用的数学框架提供了信心。
