FORRESTER, D.M. ...et al., 2015. Experimental verification of nanofluid shear-wave reconversion in ultrasonic fields. Nanoscale, 8 (10), pp. 5497-5506.
Here we present the verification of shear-mediated contributions to multiple scattering of ultrasound in suspensions. Acoustic spectroscopy was carried out with suspensions of silica of differing particle sizes and concentrations in water to find the attenuation at a broad range of frequencies. As the particle sizes approach the nanoscale, commonly used multiple scattering models fail to match experimental results. We develop a new model, taking into account shear mediated contributions, and find excellent agreement with the attenuation spectra obtained using two types of spectrometer. The results determine that shear-wave phenomena must be considered in ultrasound characterisation of nanofluids at even relatively low concentrations of scatterers that are smaller than one micrometre in diameter.
This is an Open Access Article. It is published by Royal Society of Chemistry under the Creative Commons Attribution 3.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/3.0/. The dataset which supports this article can be found at http://dx.doi.org/10.17028/rd.lboro.2056149
The authors acknowledge funding from the EPSRC,
grant number EP/L018780/1