Signal Amplitude and Phase Fluctuations Induced by Surface Waves in Ducted Sound Propagation

1961 ◽  
Vol 33 (2) ◽  
pp. 239-247 ◽  
Author(s):  
Joseph A. Scrimger
Keyword(s):  
Surface Waves ◽  
Sound Propagation ◽  
Signal Amplitude ◽  
Phase Fluctuations

Sound propagation in shallow water with surface waves

2004 ◽  
Vol 116 (4) ◽  
pp. 2550-2550
Author(s):  
Chris T. Tindle ◽  
Grant B. Deane
Keyword(s):  
Surface Waves ◽  
Shallow Water ◽  
Sound Propagation

scholarly journals Vertical and slanted sound propagation in the near-ground atmosphere : amplitude and phase fluctuations

2021 ◽  
Author(s):  
Matthew Kamrath ◽  
Vladimir Ostashev ◽  
D. Wilson ◽  
Michael White ◽  
Carl Hart ◽  
...  
Keyword(s):  
Large Scale ◽  
Sound Propagation ◽  
Microphone Arrays ◽  
Small Scale ◽  
Sound Sources ◽  
Phase Fluctuations ◽  
Turbulent Eddies ◽  
Low Altitude ◽  
Detection And Localization ◽  
Large Eddies

Sound propagation along vertical and slanted paths through the near-ground atmosphere impacts detection and localization of low-altitude sound sources, such as small unmanned aerial vehicles, from ground-based microphone arrays. This article experimentally investigates the amplitude and phase fluctuations of acoustic signals propagating along such paths. The experiment involved nine microphones on three horizontal booms mounted at different heights to a 135-m meteorological tower at the National Wind Technology Center (Boulder, CO). A ground-based loudspeaker was placed at the base of the tower for vertical propagation or 56m from the base of the tower for slanted propagation. Phasor scatterplots qualitatively characterize the amplitude and phase fluctuations of the received signals during different meteorological regimes. The measurements are also compared to a theory describing the log-amplitude and phase variances based on the spectrum of shear and buoyancy driven turbulence near the ground. Generally, the theory correctly predicts the measured log-amplitude variances, which are affected primarily by small-scale, isotropic turbulent eddies. However, the theory overpredicts the measured phase variances, which are affected primarily by large-scale, anisotropic, buoyantly driven eddies. Ground blocking of these large eddies likely explains the overprediction.

Shallow water sound propagation with surface waves

2005 ◽  
Vol 117 (5) ◽  
pp. 2783-2794 ◽  
Author(s):  
Chris T. Tindle ◽  
Grant B. Deane
Keyword(s):  
Surface Waves ◽  
Shallow Water ◽  
Sound Propagation

scholarly journals Relatioship of peaks of correlation functions of amplitude and phase fluctuations with eigen frequencies in oscillation spectrum

2015 ◽  
Vol 1 (3) ◽  
pp. 62-71
Author(s):  
Андрей Поляков ◽  
Andrey Polyakov
Keyword(s):  
Correlation Functions ◽  
Standing Waves ◽  
Cavity Resonator ◽  
Signal Amplitude ◽  
Signal Spectrum ◽  
Universal Relation ◽  
Two Dimensional ◽  
Phase Fluctuations ◽  
One Dimensional ◽  
The Difference

Method of correlation functions of signal amplitude and phase fluctuations (CFAP) is used for processing oscillations in one-dimensional and two-dimensional rectangular cavity resonator models. For all cases, a universal relation, which gives a relationship between the repetition period of peaks on CFAP functions and the difference of adjacent eigenfrequencies in the signal spectrum was obtained. It is shown that for two-dimensional standing wave, this difference can have only two values, each of which corresponds to eigenfrequencies of one-dimensional standing waves. The proposed method allows us to detect all possible one-dimensional standing waves which can occur in the object under study.

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