scholarly journals Absorption of Low-Frequency Sound Energy by Vegetation: A Laboratory Investigation

2006 ◽  
Author(s):  
Ryan J. Lee
2019 ◽  
Vol 33 (16) ◽  
pp. 1950177
Author(s):  
Xiao Liang ◽  
Jiu Hui Wu ◽  
Zhuo Zhou ◽  
Zhe Chen

Reverse horn as one of the Acoustic Black Hole (ABH) structures can be used to effectively reduce low frequency acoustic waves by focusing the sound energy. The sound waves in relatively low frequency range are focused on the tip of reverse horn, and most sound energy cannot flow out from the reverse horn’s tip. In this paper, we propose a quantitative analysis method by the bottleneck effect analogy to research the low frequency acoustic characteristics of reverse horn. Our theoretical results show that the low frequency sound wave can be focused on the tip of reverse horn, and the transmission coefficient of low frequency is proportional to the 3 power law of the reverse horn tip’s diameter. The experimental results verified our theoretical results. And the sound insulation property is studied by experiments. It is noteworthy that the insulation coefficient of two levels reverse horn whose second level tip’s diameter [Formula: see text] mm, is more than 0.92, and can increase further with the decrease of the second level horn tip’s diameter. It provides an effective and simple method for quantitatively analyzing the low frequency acoustic characteristics of the reverse horn. The proposed reverse horn has great potential applications for low frequency sound insulation control.


Author(s):  
Lisa A. Beeson ◽  
George A. Schott

Combustion turbine projects have become a popular choice for providing a clean and efficient source of electricity. However, since combustion turbines generally produce low frequency sound energy, special siting considerations should be evaluated to minimize the potential for impacts on sensitive receptors, such as residences, churches, hospitals, and schools. For successful siting of combustion turbine projects near sensitive receptors, it is necessary to incorporate noise control features into plant designs to reduce not only audible noise but also noise at frequencies which are even lower than the human ear can perceive. These extremely low frequencies can rattle walls and windows, causing pressure pulsations which may be perceived by some people, or vibration of small objects inside houses and other structures. Even “quiet” plants which include extensive noise control features may still result in perceptible low frequency noise due to the relative difficulty of attenuating low frequency sound energy. Noise attenuation options are discussed, including active, passive, and reactive technologies, along with the impacts associated with each type of design. Guidelines for siting combustion turbine power generation facilities near sensitive receptors are presented, to enable development of projects which not only meet applicable noise requirements, but also reduce the potential for community complaints.


AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045321
Author(s):  
Chi Xu ◽  
Hui Guo ◽  
Yinghang Chen ◽  
Xiaori Dong ◽  
Hongling Ye ◽  
...  

2021 ◽  
pp. 2100183
Author(s):  
Fan Xu ◽  
Siying Zhang ◽  
Guigen Wang ◽  
Daqiang Zhao ◽  
Junwei Feng ◽  
...  

1995 ◽  
Vol 97 (5) ◽  
pp. 3352-3352
Author(s):  
Daniel P. Costa ◽  
Dawn Goley ◽  
Danielle Waples ◽  
Don Croll ◽  
Burney Le Boeuf ◽  
...  

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