A review of current strategies and criteria for low‐frequency noise control from combustion turbines

1999 ◽  
Vol 105 (2) ◽  
pp. 1220-1220
Author(s):  
Robert A. Putnam ◽  
Roland Hetzel ◽  
Johannes van de Logt
Keyword(s):  
Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise

Low-frequency noise control using layered granular aerogel and limp porous media

2021 ◽  
Vol 263 (4) ◽  
pp. 2724-2729
Author(s):  
Yutong Xue ◽  
Amrutha Dasyam ◽  
J. Stuart Bolton ◽  
Bhisham Sharma
Keyword(s):  
Noise Control ◽  
Glass Fibers ◽  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Fibrous Materials ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Fibrous Media ◽  
Impedance Tube Method

The acoustic absorption of granular aerogel layers with a granule sizes in the range of 2 to 40 μm is dominated by narrow-banded, high absorption regions in the low-frequency range and by reduced absorption values at higher frequencies. In this paper, we investigate the possibility of developing new, low-frequency noise reduction materials by layering granular aerogels with traditional porous sound absorbing materials such as glass fibers. The acoustic behavior of the layered configurations is predicted using the arbitrary coefficient method, wherein the granular aerogel layers are modeled as an equivalent poro-elastic material while the fibrous media and membrane are modeled as limp media. The analytical predictions are verified using experimental measurements conducted using the normal incidence, two-microphone impedance tube method. Our results show that layered configurations including granular aerogels, fibrous materials, and limp membranes provide enhanced sound absorption properties that can be tuned for specific noise control applications over a broad frequency range.

Experimental Study on an Active Noise Control System for Turboprop Driven Aircraft

2013 ◽  
Vol 333-335 ◽  
pp. 2142-2145
Author(s):  
Qing Fu Kong ◽  
Yu Liang Dai ◽  
Shi Jian Zhu ◽  
Jia Ming Wu
Keyword(s):  
Experimental Study ◽  
Control System ◽  
Sound Source ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Experimental Platform ◽  
Active Noise

In order to find a solution to the control of low frequency noise in the cabin of turboprop driven aircraft, an experimental active noise control (ANC) system is introduced in the paper, which consists of vibroacoustic field analogue subsystem, acoustic field measurement subsystem and acoustic barrier exciter subsystem. Effects of both different spaces between the primary sound source and secondary sound source of the ANC system and different frequency noises on noise-reduction result are investigated based on the experimental platform. Results of the experiment show a significant potential of the ANC method for the control of low frequency noise in the cabin of turboprop driven aircraft.

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