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Experimental Investigation on Influence Factors of Active Noise Attenuation of Sound-insulation Ventilation Window
YU Hao-xin;CHEN Ke-an;HU Han;MA Xi-yue
   2012, 32 (3): 191-197.   DOI: 10.3969/j.issn.1006-1355.2012.03.044
Abstract1759)            Save
The factors influencing the active noise attenuation of a sound-insulation ventilation window were investigated experimentally. The window system was constructed by staggering the opening sashes of a spaced double glazing window to allow ventilation. Transparent microperforated absorbers (MPA) and sound-absorbing material were used along the ventilation path to attenuate external noise. The performances of the four-input and four-output active control system for the window with different secondary source locations and secondary-path modeling length were compared mutually. It is found that to achieve the considerable attenuation effect in the surface of the window, locations of the secondary sources should be so arranged that the effective scope of the secondary sound field can cover the inner space of the window and the noise energy can be reduced, or the sound field is directed to the internal window glass to directly control the radiation noise. If the optimal length of the secondary-path modeling cannot be achieved in actual application, a longer modeling length should be chosen appropriately to avoid degenerating the noise attenuation or leading the system instability.
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Acoustic Characteristics of the Throat of the Low-frequency Airflow Modulator within Closed Space
DONG Ming-rong;CHEN Ke-an;SUN De-yu;FANG Hou-lin
   2012, 32 (3): 113-117.   DOI: 10.3969/j.issn.1006-1355.2012.03.026
Abstract1377)            Save
The gas chamber pressure, throat flow rate and the acoustic characteristics of an airflow modulator were analyzed by using the theory of fluid mechanics and aeroacoustics. The computation results are compared with the experimental results. The changes of the throat acoustic amplitude with gas supply pressure, gas supply flow rate and working frequencies were given. The results show that the computation results can agree with the experimental results, and the throat acoustic amplitude can be improved with the increase of the gas supply pressure and flow rate.
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Physical Mechanisms of Active Acoustical Control for Double-panel Structure
ZHANG Xian-ying;CHEN Ke-an;HU Han;MA Xi-yue
   2012, 32 (2): 102-107.   DOI: 103969/j.issn.1006-1355-2012.02.025
Abstract1155)            Save
The theoretical model of a double-layer panel for active control of sound radiation was established based on the vibro-acoustic coupling equations. Then, the optimal secondary control force was obtained by minimizing the sound power of the panel. Next, the sound intensity distribution on the observed surface was calculated. Finally, the simulation results were analyzed in terms of the sound intensity in the near-field, and a preliminary conclusion for the mechanism of active control of this structure were obtained.
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Layout Optimizingation of Electro-acoustic Devices of Active Noise Control System for 110 kV Transformer
MA Xi-yue;CHEN Ke-an;HU Han
   2011, 31 (6): 109-115.   DOI: 10.3969/j.issn.1006-1355-2011.06.024
Abstract1759)            Save
The principle of active noise control using multiple secondary sources and error sensors in free special acoustic field is introduced. According to the measured sound pressure of 110kV transformer’s noise, a low-frequency noise-control strategy is proposed for the transformer with the use of multi-source arrays. The influence of different numbers of secondary sources and error sensors and their special layout on the control effect is analyzed through numerical simulation. Theoretically, the more the secondary sources and error sensors are, the better the control effect is. But excessive secondary sources and error sensors will lead to increasing of channels of the control system, so that the control system is unlikely to be implemented. Finally, considering the feasibility of the control system in physical point of view, an optimal control system which can yield good control effect with relatively less secondary sources and error sensors is made.
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Prediction and Validation of Aircraft Cabin Noise by Hybrid FE-SEA Method at Mid-frequency Range
LI Bing;CHEN Ke-an;PAN Kai;HU Ying
   2011, 31 (4): 60-63.   DOI: 10.3969/j.issn.1006-1355-2011.04.014
Abstract1853)            Save
Prediction and experimental verification of aircraft cabin noise modeled by the hybrid FE-SEA method is carried out. The method of subsystem dividing of the cabin is introduced. The cabin’s noise spectrums in mid-frequency range under 4 different excitation conditions are simulated and thereafter compared with measurement results. It is shown that the hybrid FE-SEA method based approach is more accurate than the conventional Statistical Energy Analysis (SEA) method in predicting mid-frequency noise inside the aircraft cabin.
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《Investigation of Evaluation Descriptors of Auditory Attribute of Underwater Noise in Chinese Environment》
WANG Na;CHEN Ke-an;HUANG Huang
   2009, 29 (5): 170-175.  
Abstract2349)      PDF(pc) (2346KB)(1699)       Save
Suitable evaluation descriptors are very important for reasonable subjective evaluation of auditory attribute of underwater noise. In this paper, firstly, a large number of Chinese descriptors is gained by questionnaire surveys and using onhand soundqualityevaluation descriptors. And then, according to three elements of auditory attribute, loudness, tone and acoustic quality, 97 descriptors are selected for evaluating the auditory attribute of the noises. Secondly, in order to avoid the subjectivity, the selected descriptors are divided into 10 categories by using Paired Comparison approach and Cluster Analysis method. Finally, through questionnaire survey and replaying the selected descriptors, some commonly used descriptors are chosen from these categories as the evaluation descriptors of auditory attribute of underwater noise due to the highest selection probability.
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