Physical Acoustics and Metrology of Fluids

Trusler, Martin

doi:10.1201/9781003062851

Cited by 37 publications

(41 citation statements)

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“…In order to construct realistic spectra that can be compared with observations, it is essential to take into account dissipative effects, which control the width and the amplitude of the resonance peaks 30,31 . Dissipation of acoustic modes in air is dominated by viscous friction and heat diffusion at solid boundaries, with minor contributions from bulk viscosity 30 .…”

Section: Dissipationmentioning

confidence: 99%

Acoustic spectra of a gas-filled rotating spheroid

Cébron

Nataf

et al. 2020

European Journal of Mechanics - B/Fluids

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The acoustic spectrum of a gas-filled resonating cavity can be used to indirectly probe its internal velocity field. This unconventional velocimetry method is particularly interesting for opaque fluid or rapidly rotating flows, which cannot be imaged with standard methods. This requires to (i) identify a large enough number of acoustic modes, (ii) accurately measure their frequencies, and (iii) compare with theoretical synthetic spectra. Relying on a dedicated experiment, an air-filled rotating spheroid of moderate ellipticity, our study addresses these three challenges. To do so, we use a comprehensive theoretical framework, together with finite-element calculations, and consider symmetry arguments. We show that the effects of the Coriolis force can be successfully retrieved through our acoustic measurements, providing the first experimental measurements of the rotational splitting (or Ledoux) coefficients for a large collection of modes. Our results pave the way for the modal acoustic velocimetry to be a robust, versatile, and non-intrusive method for mapping large-scale flows.Pages: 1-14

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Section: Dissipationmentioning

confidence: 99%

Acoustic spectra of a gas-filled rotating spheroid

Cébron

Nataf

et al. 2020

European Journal of Mechanics - B/Fluids

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“…30 Bulk viscous effects have long been considered mere higherorder contributions. 31 However, including the bulk viscosity in the acoustic approximation 32,33 straightforwardly explained the observed second-order fields associated with ultrasonic waves. The vorticity that is generated across a propagating wave's free surface induces a counter-oriented circulatory flow [34][35][36][37][38][39] that is also known as acoustic streaming or quartz-wind.…”

Section: Introductionmentioning

confidence: 96%

Bulk viscosity of liquid noble gases

Chatwell

Vrabec

2020

The Journal of Chemical Physics

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An equation of state for the bulk viscosity of liquid noble gases is proposed. On the basis of dedicated equilibrium molecular dynamics simulations, a multi-mode relaxation ansatz is used to obtain precise bulk viscosity data over a wide range of liquid states. From this dataset, the equation of state emerges as a two-parametric power function with both parameters showing a conspicuous saturation behavior over temperature. After passing a temperature threshold, the bulk viscosity is found to vary significantly over density, a behavior that resembles the frequency response of a one pole low-pass filter. The proposed equation of state is in good agreement with available experimental sound attenuation data.

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“…In this frame, the measurement of the speed of sound is obtained by measuring the delay time between two signals, emitted simultaneously, traveling different path lengths at the same speed. Exhaustive descriptions of the measurement principle and its implementation can be found in [4,[17][18][19] where also main corrections to the measurements are described.…”

Section: Measurement Technique and Correctionsmentioning

confidence: 99%

“…Though, only an infinitely small or infinitely large source would generate perfectly phased signals, it is possible to design the measurement cell combining source diameter and acoustic paths length in a way that diffraction corrections remains small compared to other source of uncertainty [17].…”

Section: Diffraction Correctionsmentioning

confidence: 99%

Towards a new transfer standard for speed of sound measurements in liquids at cryogenic temperatures

2021

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Measurement of fluids flows represents an unparalleled tools for the account of the transferred mass, heat and energy; however, considering the wide ranges of transported fluids flow-rates, temperatures, pressures, viscosity and densities, high accurate calibrations of ultrasonic flowmeters remain demanded.As an alternative to the usual gravimetric calibration, there is a less explored possibility to provide the traceability of the measurement through the speed of sound.In this work an ultrasonic sensor, which operates on the basis of the double pulse-echo technique is presented. This sensor is capable to provide measurements of speed of sound, fully traceable to units of length and time. Moreover, it has been optimized to operate when set both into a laboratory thermostat and into industrial plants using spools like DN50, or larger, in order to be adopted as a transfer standard for flow rate measurements. The concept behind this idea is the possibility of characterising the ultrasonic cell, namely the velocity meter, in a controlled temperature and pressure conditions in a laboratory environment. Thereafter, it is possible to connect the sensor directly to the natural gas distribution lines, nearby the industrial ultrasonic flow meters, normally used to monitor the LNG flow. This procedure would bring the significant benefit of enabling industrial flowmeters to be calibrated without the need for prior knowledge of the composition of the fluid under test, as well as avoiding the shutdown or removal of flowmeters during their calibration.The sensor has been tested and characterized performing measurements in liquid methane in the temperature range of (100 and 162) K and for pressure up to 10 MPa. The expanded relative uncertainty of the obtained speed of sound, w is U r (w) = 0.15 % (k = 2) for temperature below 130 K and U r (w) = 0.32 % (k = 2) for temperature above 130 K. The obtained values are in agreement with those available in the scientific literature and with the predictions of the Seitzmann and Wagner and GERG equation of state.Along with experimental speed of sound measurements, a deep insight of the procedures adopted to improve the stability of the sensor, the specific corrections applied considering the cryogenic working conditions and a complete analysis of the uncertainty affecting the obtained results is also discussed.

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Physical Acoustics and Metrology of Fluids

Cited by 37 publications

References 0 publications

Acoustic spectra of a gas-filled rotating spheroid

Acoustic spectra of a gas-filled rotating spheroid

Bulk viscosity of liquid noble gases

Towards a new transfer standard for speed of sound measurements in liquids at cryogenic temperatures

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