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

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 Some Analytic Results for the Study of Broadband Noise Radiation from Wings, Propellers and Jets in Uniform Motion

2003 ◽  
Vol 2 (3) ◽  
pp. 335-350 ◽  
Author(s):  
F. Farassat ◽  
J. Casper
Keyword(s):  
Correlation Function ◽  
Reference Frame ◽  
Cross Correlation ◽  
Near Field ◽  
Space Time ◽  
Broadband Noise ◽  
Uniform Motion ◽  
Far Field ◽  
Forward Motion ◽  
Radiated Noise

Alan Powell has made significant contributions to the understanding of many aeroacoustic problems, in particular, the problems of broadband noise from jets and boundary layers. In this paper, some analytic results are presented for the calculation of the correlation function of the broadband noise radiated from a wing, a propeller, and a jet in uniform forward motion. It is shown that, when the observer (or microphone) motion is suitably chosen, the geometric terms of the radiation formula become time independent. The time independence of these terms leads to a significant simplification of the statistical analysis of the radiated noise, even when the near field terms are included. For a wing in forward motion, if the observer is in the moving reference frame, then the correlation function of the near and far field noise can be related to a space-time cross-correlation function of the pressure on the wing surface. A similar result holds for a propeller in forward flight if the observer is in a reference frame that is attached to the propeller and rotates at the shaft speed. For a jet in motion, it is shown that the correlation function of the radiated noise can be related to the space-time cross-correlation of the Lighthill stress tensor in the jet. Exact analytical results are derived for all three cases. For the cases under present consideration, the inclusion of the near field terms does not introduce additional complexity, as compared to existing formulations that are limited to the far field.

Magnetic Tag Antenna for UHF Near-field and Far-Field RFID Applications

2015 ◽  
Vol 5 (2) ◽  
pp. 119
Author(s):  
Mondher Dhaouadi ◽  
M. Mabrouk ◽  
T. Vuong ◽  
A. Ghazel
Keyword(s):  
Near Field ◽  
Far Field ◽  
Rfid Applications
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