scholarly journals Localization and characterization of rotating noise sources on axial fans by means of an irregularly shaped microphone array

2021 ◽  
Vol 1909 (1) ◽  
pp. 012003
Author(s):  
O Amoiridis ◽  
R Zamponi ◽  
A Zarri ◽  
J Christophe ◽  
C Schram
Keyword(s):  
Microphone Array ◽  
Noise Sources ◽  
Axial Fans

A Comparison of Frequency-Domain Microphone Array Methods for the Characterization of Rotating Broadband Noise Sources

2019 ◽  
Vol 105 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Christof Ocker ◽  
Gert Herold ◽  
Florian Krömer ◽  
Wolfram Pannert ◽  
Ennes Sarradj ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Microphone Array ◽  
Broadband Noise ◽  
Noise Sources

scholarly journals Characterization of Noise Level Inside a Vehicle under Different Conditions

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2471 ◽  
Author(s):  
Daniel Flor ◽  
Danilo Pena ◽  
Luan Pena ◽  
Vicente A. de Sousa ◽  
Allan Martins
Keyword(s):  
Regression Analysis ◽  
Noise Level ◽  
Acoustic Noise ◽  
Experimental Setup ◽  
Strongly Correlated ◽  
Noise Levels ◽  
Noise Sources ◽  
Statistical Tools ◽  
Window Position

Vehicular acoustic noise evaluations are a concern of researchers due to health and comfort effects on humans and are fundamental for anyone interested in mitigating audio noise. This paper focuses on the evaluation of the noise level inside a vehicle by using statistical tools. First, an experimental setup was developed with microphones and a microcomputer located strategically on the car’s panel, and measurements were carried out with different conditions such as car window position, rain, traffic, and car speed. Regression analysis was performed to evaluate the similarity of the noise level from those conditions. Thus, we were able to discuss the relevance of the variables that contribute to the noise level inside a car. Finally, our results revealed that the car speed is strongly correlated to interior noise levels, suggesting the most relevant noise sources are in the vehicle itself.

Effect of Rotor-Stator Configuration in the Generation of Vortical Scales and Wake Mixing in Single Stage Axial Fans: Part II — Assessment of Vortex Sound Sources

2013 ◽  
Author(s):  
Mónica Galdo Vega ◽  
Jesus Manuel Fernandez Oro ◽  
Katia María Argüelles Díaz ◽  
Carlos Santolaria Morros
Keyword(s):  
Deep Understanding ◽  
Operating Conditions ◽  
Axial Fan ◽  
Noise Sources ◽  
Sound Sources ◽  
Time Resolved ◽  
Vortex Sound ◽  
Starting Point ◽  
Axial Fans ◽  
The Impact

This second part is devoted to the identification of vortex sound sources in low-speed turbomachinery. As a starting point, the time-resolved evolution of the vortical motions associated to the wake shear layers (reported in the first part of the present study) is employed to obtain vorticity distributions in both blade-to-blade and traverse locations throughout the axial fan stage. Following, the Powell analogy for generation of vortex sound is revisited to obtain the noise sources in the nearfield region of the fan. Both numerical and experimental databases presented previously are now post-processed to achieve a deep understanding of the aeroacoustic behavior of the vortical scales present in the flow. A LES simulation at midspan, using a 2.5D scheme, allows an accurate description of the turn-out time of the shedding vortices, within high-density meshes in the blades and vanes passages, and a correct modeling of the dynamics of turbulence. Besides, thermal anemometry has been employed with a two-wire probe to measure the planar flow in the midspan sections of the fan. Statistical procedures and signal conditioning of velocity traces have confirmed experimentally the unsteady flow patterns devised in the numerical model. The comparison of the rotor-stator and the stator-rotor configurations provides the influence of the wake mixing and the nucleation of turbulent spots in the distribution of the Powell source terms. Moreover, the relation between the turbomachine configuration and the generation of vortex sound can be established, including the impact of the operating conditions and the contributions of the interaction mechanisms.

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

Noise sources localization in the RRJ-95 aircraft pressure cabin by spherical microphone array. Part 1. Cockpit

2020 ◽  
Vol 27 (2) ◽  
pp. 37-51
Author(s):  
Petr Moshkov ◽  
Dmitry Vasilenkov ◽  
Victor Rubanovskii ◽  
Alexey Stroganov
Keyword(s):  
Microphone Array ◽  
Noise Sources

Noise sources localization in the RRJ-95 aircraft pressure cabin by spherical microphone array. Part 2. Passenger cabin

2020 ◽  
Vol 27 (3) ◽  
pp. 60-72
Author(s):  
Petr Moshkov ◽  
Dmitry Vasilenkov ◽  
Victor Rubanovskii ◽  
Alexey Stroganov
Keyword(s):  
Microphone Array ◽  
Noise Sources ◽  
Passenger Cabin

Airframe noise measurements on JAXA Jet Flying Test Bed “Hisho” using a phased microphone array

2017 ◽  
Vol 16 (4-5) ◽  
pp. 255-273 ◽  
Author(s):  
Takehisa Takaishi ◽  
Hiroki Ura ◽  
Kenichiro Nagai ◽  
Yuzuru Yokokawa ◽  
Mitsuhiro Murayama ◽  
...  
Keyword(s):  
Microphone Array ◽  
Low Frequency ◽  
Landing Gear ◽  
Frequency Resolution ◽  
Test Bed ◽  
Noise Sources ◽  
Low Frequencies ◽  
Airframe Noise ◽  
Noise Measurements ◽  
Wooden Platform

In 2015, the Japan Aerospace Exploration Agency launched the Flight demonstration of QUiet technology to Reduce nOise from High-lift configurations project to verify by flight demonstration the feasibility of practical noise-reducing aircraft modification concepts. In order to serve as a baseline for comparison before modification, airframe noise sources of the JAXA Jet Flying Test Bed “Hisho” were measured with a 30 m diameter array of 195 microphones mounted on a wooden platform built temporary beside the runway of Noto Satoyama Airport in Japan. A classical Delay and Sum in the time domain beamforming algorithm was adapted for the present study, with weight factors introduced to improve the low-frequency resolution and autocorrelations eliminated to suppress wind noise at high frequencies. In the landing configuration at idle thrust, the main landing gear, nose landing gear, and side edges of the six extended flap panels were found to be the dominant “Hisho” airframe noise sources. Deconvolution by the DAMAS and CLEAN-SC algorithms provided clearer positions of these sound sources at low frequencies. Integration of acoustical maps agreed well with the sound pressure level measured by a microphone placed at the center of the microphone array and gave detailed information about the contribution of each noise source.

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