Measurement of the sound velocity in fluids using the echo signals from scattering particles

Lenz, Michael; Böck, Martin; Kühnicke, Elfgard; Pal, J.; Cramer, A.

doi:10.1016/j.ultras.2011.07.003

Cited by 14 publications

(7 citation statements)

References 13 publications

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“…Since the water always contained fewer scattering particles, averaging was done over 30 000 measurements here. As already found in [1,2], the position of the maximum of the averaged echo signal is virtually the same as the time of flight t to the focus.…”

Section: Calculated Sound Fieldssupporting

confidence: 75%

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Non-invasive measurement of sound velocity profiles

Kühnicke

Lenz

Böck

2011

2011 IEEE International Ultrasonics Symposium

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In ultrasonics, the time of flight to the object interfaces is often the only information that is considered. From this information, one can either determine distances or sound velocities if the other value is known. A combined determination of the sound velocity and the distance of the scattering particles to the transducer makes it possible to measure sound velocity profiles. To determine distance and sound velocity simultaneously, we use the focus position as a second piece of information beside the ultrasonic time of flight. The focus position can be determined, because the echo becomes strongest when the scattering particle is located within the maximum of the sound field. Thus the position of the averaged echo signal amplitude indicates the time of flight to the focus.In previous measurements with a strongly focusing transducer with lens an accuracy of 99.9% was achieved with this method. The current presentation deals with first steps toward the measurement of sound velocity profiles. To measure a velocity profile, the focus position, i. e. the distance of the sound field maximum from the transducer, is varied by beam forming with an annular array. By using adequate calibration curves, the sound velocity on different points along the acoustic axis can be determined in dependence of the chosen set of time lags used for focusing and the time of flight corresponding to the maximum of the averaged echo signal amplitude. The measurement of the locally resolved sound velocity in media with constant sound velocity yields information about the accuracy that can be reached for varying focus distances.

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Section: Calculated Sound Fieldssupporting

confidence: 75%

“…In [1,2] a novel approach for sound velocity measurements in fluids with scattering particles was introduced. The most important characteristic is that the back wall echo or the echoes of reflectors fixed inside the fluid are not required.…”

Section: Introductionmentioning

confidence: 99%

Non-invasive measurement of sound velocity profiles

Kühnicke

Lenz

Böck

2011

2011 IEEE International Ultrasonics Symposium

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“…2). and Lenz and Kühnicke (2012) give proof of concept by measurements in fluids covering a wide range of sound velocities with a strongly focusing transducer equipped with a lens. An uncertainty in velocity determination of less than 0.1 % was achieved in a detailed measurement using water at different temperatures.…”

Section: Scattering Particle Methods For Locally Resolved Measurement mentioning

confidence: 99%

Annular arrays for novel ultrasonic measurement techniques

Wolf

Kühnicke

Kümmritz

et al. 2016

J. Sens. Sens. Syst.

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Abstract. The paper shows how the precise knowledge of the sound field of an ultrasonic annular array can contribute to the development of novel measurement techniques. Emphasis is placed on (a) a non-invasive method for sound velocity measurements in fluids using the echo signals from scattering p]articles, (b) a non-invasive method for the combined determination of thickness and sound velocity in layered structures by using a novel focusing technique, and (c) a non-scanning curvature measurement method exploiting the wave front curvature of a reflected wave. To demonstrate the methods, the principles as well as results of simulations and measurements are discussed.

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“…Since there is a measuring time which allows the processing of a number of signals, alternatively a statistical processing may be applied. Examples are the analysis of frequency components, the sound velocity measurement by using the reflection on particles [7] or inhomogeneous tissue [8] or the particle analysis itself based on a statistical approach [9]. Such techniques can be adapted to quite simpler task of amplitude or travel time measurements for level detection or media analysis.…”

Section: Statistical Evaluation For Ultrasonic Level Detectionmentioning

confidence: 99%