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Stability analysis of a noise control system in a duct by using delay differential equation

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Acta Mechanica Sinica 2009年第1期25卷 131-137页

作者： Masakazu Haraguchi MOE Key Laboratory of Structure Mechanics and control for Aircraft Nanjing University of Aeronautics and Astronautics

The paper deals with the criteria for the closed- loop stability of a noise control system in a duct. To study the stability of the system, the model of delay differential equation is derived from the propagation of acoustic wave governed by a partial differential equation of hyperbolic type. Then, a simple feedback controller is designed, and its closed- loop stability is analyzed on the basis of the derived model of delay differential equation. The obtained criteria reveal the influence of the controller gain and the positions of a sensor and an actuator on the closed-loop stability. Finally, numerical simulations are presented to support the theoretical results.

关键词： Stability analysis Delay differential equation Closed-loop stability noise control Acoustic system

Research on noise control for Ventilators with Resonance

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Journal of China University of Mining and Technology 2006年第1期16卷 25-27页

作者： GUO Chu-wen SUN Fei-hong College of Mechanical and Electrical Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China Xuzhou Institute of Architectural Technology Xuzhou Jiangsu 221008 China

A study was carried out to control the noise produced by the ventilators at the Luling coalmine, which had caused serious noise pollution to the residents living around the mine for a long time. The main noise source was found to be the dynamic noise at the outlet of the diffuser. The frequency of its peak value was 250 Hz. A special brick with a resonant frequency of 250 Hz was designed to eliminate this noise. The diffusion of a lower frequency noise has been successfully controlled by the installation of a noise-eliminating tower above the diffuser outlet. The detection results show that the noise in the nearby residential area has been lowered to an average 55.3dB(A) in the daytime from 69.8dB(A) and to 48.4dB(A) at night from 65.8dB(A).

关键词： Resonance noise ventilator noise control coalmine

noise control Solutions for Diesel Generator Sets

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Journal of Power and Energy Engineering 2023年第12期11卷 36-43页

作者： Mahmood Sawilam Saleh Elkelani Babaa Ahmed Al Haddabi Saheed Wasiu Tariq Hussain Martin Khzouz John Pillia Department of Systems Engineering Military Technological College (Affiliated with University of Portsmouth UK) Muscat Oman

A persistent challenge for Oman's energy infrastructure was the deafening rumble of diesel generators. The Silent Generator Project addressed this challenge, developing advanced generators that deliver power quietly and efficiently. Diesel generators have historically been notorious for being noisy and vibrational, making them unsuitable for sensitive environments. To dramatically reduce noise levels, the project utilized innovative materials and design modifications to ensure reliable and quiet electricity for various applications. In all directions, the project advanced the knowledge of noise reduction through rigorous testing and meticulous integration of insulators and mufflers. As a result, quieter, more sustainable energy production is on the way, marking a major advance in silent generator technology. Furthermore, the Silent Generator Project lays the foundation for more efficient and environmentally friendly diesel generator technologies in the future. As a result of this research, a new standard for quieter, greener energy generation is established, demonstrating the critical role noise reduction plays in energy generation. Additionally, this work also suggests future diesel generator technologies that are more efficient and environmentally friendly. As a result of this research, a new standard for quieter, greener energy generation is set, demonstrating the critical role noise reduction plays in energy generation.

关键词： Diesel Generator noise control Design Solution Silent Temperature Sustainability

Subjective annoyance caused by indoor low-level and low frequency noise and control method

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Journal of Environmental Sciences 2005年第1期17卷 135-140页

作者： DIGuo-qing ZHANGBang-jun SHANGQi DepartmentofEnvironmentalScience ZhejiangUniversityHangzhou310028China

The influence of low_level noise has not been widely noticed. This paper discovered that low_level and low frequency noise(A_weighted equivalent level L eq <45 dB) causes higher probability of subjective annoyance. Th... 详细信息

The influence of low_level noise has not been widely noticed. This paper discovered that low_level and low frequency noise(A_weighted equivalent level L eq noise in this study; there is preferable relationship between the indoor noise and noise annoyance at low frequency noise level. Study indicated at the same centered noise level, the change of annoyance probability is mainly caused by the change of the frequency spectrum characteristic of the indoor noise. Under low noise level environment, without change of the medium_low frequency noise, the slight increase of medium_high frequency noise level with the help of noise sheltering effect can significantly reduce the noise annoyance. This discovery brings a new resolution on how to improve the environmental quality of working or living places. A noise control model is given in this study according to the acoustic analysis.

关键词： low-level noise subjective annoyance threshold level structural noise indoor noise noise control

noise control of a Two Stroke Engine Car

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Journal of Beijing Institute of Technology 1998年第2期7卷 203-209页

作者：葛蕴珊吴思进刘福水张付军黄英北京理工大学车辆工程学院

Aim To control the noise of two stroke engine Methods On the basis of noise identification,a new muffler and acoustic shield were designed,Results the car's pass-by noise below the national limit Conclusion through proper noise controlling measures,the pass-by noise of two stroke engines could be reduced under national permitting limit.

关键词： noise control two stroke engine vehicle

noise Pollution Reduction through a Novel Optimization Procedure in Passive control Methods

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Computer Modeling in Engineering & Sciences 2022年第4期131卷 1-18页

作者： Haojie Lian Leilei Chen Xiao Lin Wenchang Zhao Stephane P.A.Bordas Mingdong Zhou Key Laboratory of In-Situ Property-Improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation Huanghuai UniversityZhumadian463000China College of Architecture and Civil Engineering Xinyang Normal UniversityXinyang464000China The York Management School University of YorkYorkYO105DDUK CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of ChinaHefei230027China Institute for Computational Engineering Faculty of ScienceTechnology and CommunicationUniversity of LuxembourgLuxembourgSA28PPUK School of Engineering Cardiff UniversityCardiffCF243AAUK Shanghai Key Laboratory of Digital Manufacture for Thin-Walled Structures School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

This paper proposes a novel optimization framework in passive control techniques to reduce noise *** geometries of the structures are represented by Catmull-Clark subdivision surfaces,which are able to build gap-free Computer-Aided Design models and meanwhile tackle the extraordinary points that are commonly encountered in *** acoustic fields are simulated using the isogeometric boundary elementmethod,and a density-based topology optimization is conducted to optimize distribution of sound-absorbing materials adhered to structural *** approach enables one to perform acoustic optimization from Computer-Aided Design models directly without needingmeshing and volume parameterization,thereby avoiding the geometric errors and time-consuming preprocessing steps in conventional simulation and optimization *** effectiveness of the present method is demonstrated by three dimensional numerical examples.

关键词： noise control topology optimization Catmull-Clark subdivision surfaces isogeometric analysis boundary element methods

Prediction and control of Wheel/Rail noise for Rail Transit(Abstract of the ***)

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中国铁道科学 2006年第1期 139-139页

作者： XUZhi-sheng1,2,ZHAI Wan-ming1(1.Traction Power State Key Laboratory,Southwest Jiaotong University,Chengdu Sichuan 610031,China 2.The Forth Survey and Design Institute of China Rail way,Wuhan 430063,China)

Adaptive Active control of Low Frequency noise in a Duct 

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Journal of Beijing Institute of Technology 1999年第3期8卷 318-323页

作者：李传光李悟韩秀苓北京理工大学自动控制系北京100081

Aim To study a method realizing noise control for a physical model of progressive wave in a duct. Methods A mathematical model was constructed and a transfer function of the adaptive system for noise control was also worked out; moreover, the effects of some algorithms such as RLS,LMS and LSL on noise control were analyzed and compared. Results Without the feedback of sound, the mean noise reduce value(MNRV) of 27 5 dB for broadband noise from 0 to 500?Hz in frequency were achieved. When acoustic feedback took place and an air stream loudspeaker was used, the MNRV was only about 4 9?dB. But if the loudspeaker had a plain frequency feature, MNRV was improved by 10 2?dB. Conclusion The technique is applied to ruducing the noise from engines' exhausted gas pipes. It is, in principle, used for noise cancelling in a closed three dimensional space.

关键词： noise control adaptive mean noise reduce value(MNRV)

Carrier frequency and symbol rate estimation based on cyclic spectrum

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Journal of Systems Engineering and Electronics 2020年第1期31卷 37-44页

作者： CAO Sisi ZHANG Weiyan Institute of Computer Applications China Academy of Engineering Physics

Carrier frequency and symbol rate estimation are the main contents of parameter estimation,which is the basis of modulation recognition and further processing of signals especially in non-cooperative *** the development of wireless communication,the signal transmission environment has become increasingly bad,causing more difficulties in parameter *** is well known that the signal cycle spectrum is robust to noises and signal parameters are closely *** practice,it is impossible to calculate the cyclic spectrum of infinite length data *** using finite length data to obtain a cycle spectrum,the truncation noise is induced,resulting in *** is necessary to overcome the influence of noises in order to improve the detection ability of discrete spectral *** improved method of the discrete spectral line extraction algorithm is proposed by reflecting the amplitude advantage of discrete spectral lines through salient features of continuous noises in discrete spectral line neighborhood.

关键词： digital modulation signal carrier frequency symbol rate cyclic spectrum noise control