Eddy-current non-inertial displacement sensing for underwater infrasound measurements

Donskoy, Dimitri; Cray, Benjamin A.

doi:10.1121/1.3577576

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…5 Although the sensor was designed for underwater measurements, it is sensitive enough for measurements in-air. The sensor consists of a hollow aluminum sphere of 1.9 cm diameter, suspended, with two strings, in a plastic housing.…”

Section: Experimental Verification Of the Amplification Effectmentioning

confidence: 99%

Horns as particle velocity amplifiers

Donskoy

Cray

2011

The Journal of the Acoustical Society of America

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Preliminary measurements and numerical predictions reveal that simple, and relatively small, horns generate remarkable amplification of acoustic particle velocity. For example, below 2 kHz, a 2.5 cm conical horn has a uniform velocity amplification ratio (throat-to-mouth) factor of approximately 3, or, in terms of a decibel level, 9.5 dB. It is shown that the velocity amplification factor depends on the horn's mouth-to-throat ratio as well as, though to a lesser degree, the horn's flare rate. A double horn configuration provides limited additional gain, approximately an increase of up to 25%.

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Section: Experimental Verification Of the Amplification Effectmentioning

confidence: 99%

Horns as particle velocity amplifiers

Donskoy

Cray

2011

The Journal of the Acoustical Society of America

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“…A worldwide network of 60 infrasound stations is being established to help monitor compliance with the treaty [3] . Various non-contact, direct-sensing techniques exist, including laser-based interferometric or time-of-flight, capacitive, inductive, optical, and eddy-current (EC) sensing methods [4,5] . Infrasound detection using traditional sensors is based on piezoelectric principles [6] .…”

mentioning

confidence: 99%

“…Eddycurrent (EC) sensors that can perform well in water, are stable with temperature and relatively inexpensive, and have a small form. The EC infrasound sensor reported by Donskoy et al [4] can detect acoustic signals below 1 Hz at displacement levels of fractions of nanometers. However, when using multiple probes, EC probes interact if mounted sufficiently close to one another.…”

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Infrasound detection by laser diode self-mixing interferometry

Li¹,

Huang²,

Sun³

2013

中国光学快报

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An alternative technique for infrasound detection based on the self-mixing (SM) interference of a laser diode is described. The principle involved is the dependence of the power emitted by the laser diode on infrasound-induced membrane vibration. The Fourier transform and fringe-counting methods are used to analyze the self-mixing signal. Infrasound signals are experimentally measured from 2 to 20 Hz with a resolution of 0.25, and the results well agree with the theoretical ones.OCIS codes: 120.7280, 230.1040, 280.3420. doi: 10.3788/COL201311.021201.The nominal range of human hearing extends from approximately 20 Hz to 20 kHz. Inaudible sound waves with frequencies below 20 Hz are termed infrasound. These waves can be caused by many natural and anthropogenic sources, such as volcanic eruptions, earthquakes, typhoon, nuclear explosions, spacecraft, and so on [1] . Renewed interest in the detection of infrasound energy in the atmosphere appeared with the creation of the Comprehensive Nuclear-Test-Ban Treaty Organization [2] . A worldwide network of 60 infrasound stations is being established to help monitor compliance with the treaty [3] . Various non-contact, direct-sensing techniques exist, including laser-based interferometric or time-of-flight, capacitive, inductive, optical, and eddy-current (EC) sensing methods [4,5] . Infrasound detection using traditional sensors is based on piezoelectric principles [6] . Bruel and Kjaer market a low-noise microphone (type 4193) that responds at frequencies as low as 0.05 Hz and has impressive noise properties. The optical fiber infrasound sensor (OFIS) is an innovative device comprising two fibers (typically extending from 100 to 1 000 m) connected as a Michelson, Mach-Zehnder, or equivalent interferometer. Considering that the OFIS is longer than the distance over which wind-induced pressure changes are coherent, the effects of wind noise on infrasound detection is reduced, and the signal-to-noise ratio (SNR) is increased over a wide bandwidth [6,7] . These sensors enable accurate measurements but require many optical components, which make these sensors expensive to install and maintain. Eddycurrent (EC) sensors that can perform well in water, are stable with temperature and relatively inexpensive, and have a small form. The EC infrasound sensor reported by Donskoy et al. [4] can detect acoustic signals below 1 Hz at displacement levels of fractions of nanometers. However, when using multiple probes, EC probes interact if mounted sufficiently close to one another.Another alternative technique based on the self-mixing (SM) effect in a laser diode (LD) is presented in this letter.This method has been widely investigated over the last decades particularly for displacement measurements [8−11] . A self-mixing (SM) sensing scheme is advantageous because it does not require an optical interferometer external to the source and an external photo-detector. The laser itself is also used both as a source and a detector, resulting in a very simple and compact setup [12] . In this l...

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Research of eddy current sensors applied to displacement-based vector hydrophones

Hong

2021

Sensors and Actuators A: Physical

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Eddy-current non-inertial displacement sensing for underwater infrasound measurements

Cited by 4 publications

References 8 publications

Horns as particle velocity amplifiers

Horns as particle velocity amplifiers

Infrasound detection by laser diode self-mixing interferometry

Research of eddy current sensors applied to displacement-based vector hydrophones

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