scholarly journals REDUCING THE NOISE INTENSITY OF SUBSONIC TURBULENT JETS USING NOISE-ATTENUATING DEVICES

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 73-78
Author(s):  
Oleg Sitknikov ◽  
Pavel Nakoryakov ◽  
Margarita Mironova ◽  
Ksenia Valeeva
Keyword(s):  
Noise Intensity ◽  
Turbulent Jets ◽  
Aircraft Noise ◽  
Acoustic Fields ◽  
Noise Sources ◽  
Acoustic Characteristics ◽  
Research Results

Reducing aircraft noise is a pressing issue. To solve it, information is needed on the parameters of the acoustic fields of noise sources. A study was made of the acoustic characteristics of models of noise-attenuating devices. Analysis of the research results revealed the design of the noise-attenuating device with the greatest effect. Based on the results of the research, a noise-attenuating device for the «Ansat» helicopter was developed. The proposed measures to reduce the acoustic pulsations of the engines of a light helicopter.

Feature extraction of flow and acoustic fields for identification of noise sources and improvement of performance of small axial fans

2020 ◽  
Vol 2020 (0) ◽  
pp. OS07-05
Author(s):  
Wataru OBAYASHI ◽  
Hikaru AONO ◽  
Tomoaki TATSUKAWA ◽  
Kozo FUJII ◽  
Koichi TAKEDA ◽  
...  
Keyword(s):  
Feature Extraction ◽  
Acoustic Fields ◽  
Noise Sources ◽  
Axial Fans

Closed-form analytical approach for calculating noise contours of directive aircraft noise sources

2021 ◽  
Author(s):  
Daniel C. Amargianitakis ◽  
Rodney H. Self ◽  
Antonio J. Torija ◽  
Anderson Proenca ◽  
Athanasios P. Synodinos
Keyword(s):  
Closed Form ◽  
Analytical Approach ◽  
Aircraft Noise ◽  
Noise Sources

scholarly journals Characterizing distinct components of tactical aircraft noise sources

2020 ◽  
Vol 147 (5) ◽  
pp. 3550-3564
Author(s):  
David F. Van Komen ◽  
Blaine M. Harker ◽  
Tracianne B. Neilsen ◽  
Kent L. Gee ◽  
S. Hales Swift ◽  
...  
Keyword(s):  
Aircraft Noise ◽  
Noise Sources

scholarly journals Aeroacoustics of Turbulent Jets: Flow Structure, Noise Sources, and Control

2006 ◽  
Vol 49 (4) ◽  
pp. 1078-1085 ◽  
Author(s):  
Ephraim Jeff GUTMARK ◽  
Bryan William CALLENDER ◽  
Steve MARTENS
Keyword(s):  
Flow Structure ◽  
Turbulent Jets ◽  
Noise Sources ◽  
And Control

SURFACE-GENERATED NOISE IN AN OCEAN WAVEGUIDE WITH A TRANSITION LAYER OF CONTINUOUSLY VARYING DENSITY AND SOUND SPEED

1999 ◽  
Vol 07 (04) ◽  
pp. 253-268 ◽  
Author(s):  
JIN-YUAN LIU ◽  
CHEN-FEN HUANG
Keyword(s):  
Continuous Spectrum ◽  
Sound Speed ◽  
Noise Intensity ◽  
Normal Modes ◽  
Vertical Direction ◽  
Sediment Layer ◽  
Noise Generation ◽  
Oceanic Waveguide ◽  
Noise Sources ◽  
Noise Field

This paper considers the noise field generated by surface random processes in an oceanic environment with a sediment layer possessing a continuously varying density and sound-speed profile. This model closely resembles the oceanic waveguide environment and therefore enables the simulation of surface noise generation. Many results of the noise field were generated, including the noise intensity distribution, vertical and horizontal correlations. It is demonstrated that the noise intensity may be affected by the stratification mainly through the continuous spectrum, in that the continuous spectrum is equally important as the normal modes in the present analysis. Moreover, the results for the correlations show that the noise field in the horizontal direction becomes more coherent when the noise sources are more correlated, while in the vertical direction, the results tend to reverse. The horizontal correlations of the noise field due to surface random sources with nonisotropic power spectrum, such as nonisotropic Gaussian and Pierson–Moskowitz, were generated and analyzed.

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