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Updated: Dec 31, 2025

Microparticle Manipulation by Standing Surface Acoustic Waves with Dual-frequency Excitations
Published on: August 21, 2018
Increasing the performance of active noise control systems on ground with two vertical reflecting surfaces with an
Jiaxin Zhong1, Jiancheng Tao1, Xiaojun Qiu2
1Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093, China.
Abstract:
This paper investigates the feasibility of increasing the noise reduction performance of active noise control (ANC) systems on ground by introducing two vertical reflecting surfaces with an included angle. By using the image source method, the theory of sound wave propagation in a wedge-shaped reflector and the integral equation method, the noise reduction of the ANC systems with two infinitely large or finite size reflecting surfaces with different included angles are studied. It is demonstrated that the noise reduction of the system can be increased significantly with two reflecting surfaces after optimizing their included angle and size. The simple empirical formulas for the optimal included angle of the surfaces and the noise reduction are presented. It is found that the noise reduction at 500 Hz increases by 13.6 dB when two vertical reflecting surfaces are arranged with an optimal angle of 125° and the source distance is 0.1 m. By optimizing the size of the reflecting surfaces to about 0.35 of the wavelength, the noise reduction can be further increased by approximately 2.8 dB. The mechanisms for the performance improvement are disclosed, and the experiments are conducted to validate the results.
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