Instantaneous intensity

Heyser, Richard C.

doi:10.1121/1.2023514

Cited by 10 publications

(13 citation statements)

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“…Jacobsen 6 suggests that when measuring the instantaneous complex sound intensity in a nonmonochromatic sound field it is preferable to use a narrow band source in order to apply the complex representation of the instantaneous intensity suggested by Heyser 7 . In this respect, the study of instantaneous complex intensity in a non-monochromatic sound field is challenging and so if one is attempting to compare prediction and experiment it is sensible first to simplify the problem and use only a monochromatic sound field.…”

Section: Complex Intensity Definitionsmentioning

confidence: 99%

“…The first technique is based on the method proposed by Heyser 7 , who defines the instantaneous active and reactive intensity as…”

Section: Complex Intensity Definitionsmentioning

confidence: 99%

“…This means that for a non-monochromatic sound field multiple definitions for instantaneous complex intensity are possible. Jacobsen 6 reviews a number of alternative definitions and concludes that the one suggested by Heyser 7 is probably the most useful.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, if one also studies a stationary sound field then the reactive intensity is likely to be significant over the entire length of the duct because both incident and reflected waves will propagate, so that one is not restricted solely to measuring close to a region of high modal scattering. Accordingly, this article begins in Section II by reviewing two methods of representing instantaneous complex intensity measurements, the methods of Heyser 7 and Stanzial and Prodi 10 . Here, use is made of a simple duct acoustics model in order to demonstrate some of the advantages and disadvantages of each method for the measurement of instantaneous intensity.…”

Section: Introductionmentioning

confidence: 99%

“…Here, Heyser 7 uses Hilbert transforms to decompose the instantaneous intensity into real and imaginary components, which are shown by Jacobsen 6 to be generalisations of the instantaneous complex intensity used for monochromatic sound fields. A series of articles later introduce an alternative definition for instantaneous intensity in a general nonmonochromatic sound field [8][9][10] .…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Measurement of complex acoustic intensity in an acoustic waveguide

Duan

Kirby²,

Prisutova³

et al. 2013

The Journal of the Acoustical Society of America

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Acoustic intensity is normally treated as a real quantity, but in recent years many articles have appeared in which intensity is treated as a complex quantity where the real (active) part is related to local mean energy flow, and the imaginary (reactive) part to local oscillatory transport of energy. This offers the potential to recover additional information about a sound field and then to relate this to the properties of the sound source and the environment that surrounds it. However, this approach is applicable only to a multi-modal sound fields, which places significant demands on the accuracy of the intensity measurements. Accordingly, this article investigates the accuracy of complex intensity measurements obtained using a tri-axial Microflown intensity probe by comparing measurement and prediction for sound propagation in an open flanged pipe. Under plane wave conditions comparison between prediction and experiment reveals good agreement, but when a higher order mode is present the reactive intensity field becomes complicated and agreement is less successful. It is concluded that the potential application of complex intensity as a diagnostic tool is limited by difficulties in measuring reactive intensity in complex sound fields when using current state of the art acoustic instrumentation.3

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Section: Complex Intensity Definitionsmentioning

confidence: 99%

“…The first technique is based on the method proposed by Heyser 7 , who defines the instantaneous active and reactive intensity as…”

Section: Complex Intensity Definitionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Measurement of complex acoustic intensity in an acoustic waveguide

Duan

Kirby²,

Prisutova³

et al. 2013

The Journal of the Acoustical Society of America

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Panoramic recording and reproduction of multichannel audio using a circular microphone array

Hacıhabiboğlu

Cvetković

2009

2009 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics

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Multichannel audio reproduction generally suffers from one or both of the following problems: i) the recorded audio has to be artificially manipulated to provide the necessary spatial cues, which reduces the consistency of the reproduced sound field with the actual one, and ii) reproduction is not panoramic, which degrades realism when the listener is not seated in a desired ideal position facing the center channel. A recording method using a circularly symmetric array of differential microphones, and a reproduction method using a corresponding array of loudspeakers is presented in this paper. Design of microphone directivity patterns to achieve a panoramic auditory scene is discussed. Objective results in the form of active intensity diagrams are presented.

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Vector Acoustic Analysis of Time-Separated Modal Arrivals From Explosive Sound Sources During the 2017 Seabed Characterization Experiment

Dahl

Dall’Osto

2020

IEEE J. Oceanic Eng.

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The Intensity Vector Autonomous Recorder (IVAR) is a system that records four coherent channels of acoustic data continuously: one channel for acoustic pressure and three channels associated with a triaxial accelerometer from which acoustic particle velocity is obtained. IVAR recorded the vector acoustic field in broadband signals originating from Signal, Underwater Sound (SUS) (Mk-64) charges deployed at 5-13-km range from the fixed IVAR site (mean depth 74.4 m) as part of the 2017 Seabed Characterization Experiment (SBCEX) designed to study the acoustics of fine-grained muddy sediments. Sufficient geometric dispersion at these ranges permitted unambiguous identification of up to four modes as a function of frequency for frequencies less than 80 Hz. From time-frequency analysis of the dispersed arrivals, a single mode (n) and single-frequency (f i) properties are identified at peaks in the narrowband scalar field, with time dependence corresponding to mode group speed. At these time-frequency addresses, four quantities derived from the vector acoustic measurements are formed by coherent combination of pressure and velocity channels: first, modal phase speed; second, circularity, a measure of the normalized curl of active intensity; third, depth-dependent mode speed of energy; and fourth, vertical component of reactive intensity normalized by scalar intensity. A means to compute these quantities theoretically is provided, and a comparison of model results based on a notional geoacoustic representation for the SBCEX experimental area consisting of a single low-speed mud layer over a half-space area versus a Pekeris representation based on the same half-space shows a striking difference, with the field observations also clearly at variance with the Pekeris representation. A fundamental property of mode 2, observed at the IVAR location, is a change in sign for circularity and vertical reactive intensity near 37 Hz that is posited as a constraint observation for mode 2 that must be exhibited by any geoacoustic model that includes a low-speed mudlike layer applied to this location.

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Instantaneous intensity

Cited by 10 publications

References 0 publications

Measurement of complex acoustic intensity in an acoustic waveguide

Measurement of complex acoustic intensity in an acoustic waveguide

Panoramic recording and reproduction of multichannel audio using a circular microphone array

Vector Acoustic Analysis of Time-Separated Modal Arrivals From Explosive Sound Sources During the 2017 Seabed Characterization Experiment

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