Title
Ultrasonic backscattering and microstructure in sheared concentrated suspensions
Date Issued
01 March 2020
Access level
open access
Resource Type
journal article
Author(s)
Aix-Marseille Univeristy
Publisher(s)
Acoustical Society of America
Abstract
Quantitative ultrasound techniques based on the parametrization of the backscatter coefficient (BSC) are used to characterize concentrated particle suspensions. Specifically, a scattering model is fit to the measured BSC and the fit parameters can provide local suspension properties. The scattering models generally assume an isotropic microstructure (i.e., spatial organization) of the scatterers, whereas the sheared concentrated suspensions can develop an anisotropic microstructure. This paper studied the influence of the shear-induced anisotropic microstructure of concentrated suspensions on the ultrasonic backscattering. Experiments were conducted on suspensions of polymethylmetacrylate spheres (5.8 μm in radius) sheared in a Couette flow device to obtain anisotropic microstructure and then mixed by hand to obtain isotropic microstructure. Experimental structure factors that are related to the spatial distribution of sphere positions were obtained by comparing the BSCs of one concentrated and one diluted suspension. Finally, Stokesian dynamics numerical simulations of sheared concentrated suspensions are used to determine the pair correlation function, which is linked to the Fourier transform of the structure factor. The experimental structure factors are found to be in good agreement with numerical simulations. The numerical simulation demonstrates that the angular-dependent BSCs and structure factors are caused by the shear-induced anisotropic microstructure within the suspension.
Start page
1359
End page
1367
Volume
147
Issue
3
Language
English
OCDE Knowledge area
Física y Astronomía
Ciencias naturales
Scopus EID
2-s2.0-85081127754
Source
Journal of the Acoustical Society of America
ISSN of the container
00014966
Sponsor(s)
We would like to thank Alain Ciffreo from INPHYNI UMR 7010 for providing the Stokesian dynamics simulation data, Bloen Metzger from IUSTI UMR 7343 for helping in designing the Couette flow device, as well as P. Cervetti, S. Noel from IUSTI UMR 7343 and V. Long from LMA UMR 7031 for building the experimental set up. This work was supported by the French National Research Agency (Grant No. ANR-15-CE19-0017), and the Labex MEC (Grant No. ANR-10-LABX-0092).
Sources of information:
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