scholarly journals Frequency-dependent jet noise source localization using cross-correlation between near and far-field microphone arrays

2017 ◽  
Author(s):  
Jacob A. Ward ◽  
S. Hales Swift ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Koji Okamoto ◽  
...  
Keyword(s):  
Source Localization ◽  
Cross Correlation ◽  
Noise Source ◽  
Jet Noise ◽  
Microphone Arrays ◽  
Far Field ◽  
Frequency Dependent

scholarly journals Jet-Surface Interaction Test: Phased Array Noise Source Localization Results

2012 ◽  
Author(s):  
Gary G. Podboy
Keyword(s):  
Source Localization ◽  
Phased Array ◽  
Noise Source ◽  
Jet Noise ◽  
Companion Paper ◽  
Far Field ◽  
Sound Waves ◽  
Axial Distribution ◽  
Noise Sources ◽  
Interaction Test

An experiment was conducted to investigate the effect that a planar surface located near a jet flow has on the noise radiated to the far-field. Two different configurations were tested: 1) a shielding configuration in which the surface was located between the jet and the far-field microphones, and 2) a reflecting configuration in which the surface was mounted on the opposite side of the jet, and thus the jet noise was free to reflect off the surface toward the microphones. Both conventional far-field microphone and phased array noise source localization measurements were obtained. This paper discusses phased array results, while a companion paper discusses far-field results. The phased array data show that the axial distribution of noise sources in a jet can vary greatly depending on the jet operating condition and suggests that it would first be necessary to know or be able to predict this distribution in order to be able to predict the amount of noise reduction to expect from a given shielding configuration. The data obtained on both subsonic and supersonic jets show that the noise sources associated with a given frequency of noise tend to move downstream, and therefore, would become more difficult to shield, as jet Mach number increases. The noise source localization data obtained on cold, shock-containing jets suggests that the constructive interference of sound waves that produces noise at a given frequency within a broadband shock noise hump comes primarily from a small number of shocks, rather than from all the shocks at the same time. The reflecting configuration data illustrates that the law of reflection must be satisfied in order for jet noise to reflect off of a surface to an observer, and depending on the relative locations of the jet, the surface, and the observer, only some of the jet noise sources may satisfy this requirement.

Calculating the frequency-dependent apparent source location using peak cross-correlation between near-field and far-field microphone arrays

2017 ◽  
Vol 142 (4) ◽  
pp. 2514-2514
Author(s):  
Jacob A. Ward ◽  
S. Hales Swift ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Koji Okamoto ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Near Field ◽  
Source Location ◽  
Microphone Arrays ◽  
Far Field ◽  
Frequency Dependent ◽  
Apparent Source

Evaluation of Jet Noise Sources by Cross-Correlation of Far Field icrophone Signals

AIAA Journal ◽  
1974 ◽  
Vol 12 (5) ◽  
pp. 583-590 ◽  
Author(s):  
S. P. PARTHASARATHY
Keyword(s):  
Cross Correlation ◽  
Jet Noise ◽  
Far Field ◽  
Noise Sources

Correction: Broadband Airfoil-Noise Source Localization by Microphone Arrays and Modeling of a Swept Free-Tip Blade

2018 ◽  
Author(s):  
Gyuzel R. Yakhina ◽  
Michel Roger ◽  
Arthur Finez ◽  
Valentin Baron ◽  
Stephane Moreau ◽  
...  
Keyword(s):  
Source Localization ◽  
Noise Source ◽  
Microphone Arrays

Jet Noise Source Distribution from Far-Field Cross Correlations

AIAA Journal ◽  
1977 ◽  
Vol 15 (6) ◽  
pp. 771-772 ◽  
Author(s):  
L. Maestrello ◽  
Chen-Huei Liu
Keyword(s):  
Noise Source ◽  
Jet Noise ◽  
Source Distribution ◽  
Far Field ◽  
Cross Correlations

Machine listening in combination with microphone arrays for noise source localization and identification

2017 ◽  
Vol 141 (5) ◽  
pp. 3964-3964
Author(s):  
Markus Müller-Trapet ◽  
Jordan Cheer ◽  
Filippo M. Fazi ◽  
Julie Darbyshire ◽  
J. Duncan Young
Keyword(s):  
Source Localization ◽  
Noise Source ◽  
Microphone Arrays ◽  
Machine Listening

Effects of Jet Noise Source Distribution on Acoustic Far-Field Measurements

2012 ◽  
Vol 11 (7-8) ◽  
pp. 885-915 ◽  
Author(s):  
Ching-Wen Kuo ◽  
Jérémy Veltin ◽  
Dennis K. McLaughlin
Keyword(s):  
Noise Source ◽  
Jet Noise ◽  
Field Measurements ◽  
Source Distribution ◽  
Far Field

scholarly journals The sources of jet noise: experimental evidence

2008 ◽  
Vol 615 ◽  
pp. 253-292 ◽  
Author(s):  
CHRISTOPHER K. W. TAM ◽  
K. VISWANATHAN ◽  
K. K. AHUJA ◽  
J. PANDA
Keyword(s):  
High Speed ◽  
Noise Source ◽  
Jet Noise ◽  
Polar Angle ◽  
Sound Field ◽  
Source Distribution ◽  
Far Field ◽  
Noise Sources ◽  
Directional Information ◽  
Jet Mixing

The primary objective of this investigation is to determine experimentally the sources of jet mixing noise. In the present study, four different approaches are used. It is reasonable to assume that the characteristics of the noise sources are imprinted on their radiation fields. Under this assumption, it becomes possible to analyse the characteristics of the far-field sound and then infer back to the characteristics of the sources. The first approach is to make use of the spectral and directional information measured by a single microphone in the far field. A detailed analysis of a large collection of far-field noise data has been carried out. The purpose is to identify special characteristics that can be linked directly to those of the sources. The second approach is to measure the coherence of the sound field using two microphones. The autocorrelations and cross-correlations of these measurements offer not only valuable information on the spatial structure of the noise field in the radial and polar angle directions, but also on the sources inside the jet. The third approach involves measuring the correlation between turbulence fluctuations inside a jet and the radiated noise in the far field. This is the most direct and unambiguous way of identifying the sources of jet noise. In the fourth approach, a mirror microphone is used to measure the noise source distribution along the lengths of high-speed jets. Features and trends observed in noise source strength distributions are expected to shed light on the source mechanisms. It will be shown that all four types of data indicate clearly the existence of two distinct noise sources in jets. One source of noise is the fine-scale turbulence and the other source is the large turbulence structures of the jet flow. Some of the salient features of the sound field associated with the two noise sources are reported in this paper.

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