TY - JOUR
T1 - A non-invasive stochastic-optical method (SOM) for estimating the volume fraction in granular flows
T2 - 26th A.I.VE.LA. Annual Meeting
AU - Sarno, Luca
AU - Nicolina Papa, Maria
AU - Tai, Yih Chin
AU - Carleo, Luigi
AU - Villani, Paolo
N1 - Publisher Copyright:
© 2019 IOP Publishing Ltd. All rights reserved.
PY - 2019/6/5
Y1 - 2019/6/5
N2 - Granular flows are involved in geophysical phenomena and industrial applications. The knowledge of the volume fraction is essential for better understanding their dynamics. Indeed, this quantity is highly coupled with the rheology of granular media. Here, we investigated the performance of the stochastic-optical method (SOM), proposed by [Sarno et al. Granular Matter (2016) 18: 80]. The method works thanks to highly-controlled illumination conditions, guaranteed by a flickering-free planar lamp, and uses a high-speed digital camera. Namely, the indirect estimation of the near-wall volume fraction c3D is made possible by the estimation of a quantity, called two-dimensional volume fraction c2D , which is measurable through an opportune binarization of gray-scale images. With the purpose of assessing the performance of the SOM method on rectangular interrogation windows with different aspect ratios, we present a novel experimental campaign on dispersions of matte-white plastic beads immersed in a dense fluid, where the angle of incidence of light was 25. Moreover, we explored various settings of the binarization algorithm, incorporated in the SOM method. The accuracy of the method is found to be reasonably high with a root-mean-square error on c3D lower than 0.03 for a wide range of settings and independently from the aspect ratio.
AB - Granular flows are involved in geophysical phenomena and industrial applications. The knowledge of the volume fraction is essential for better understanding their dynamics. Indeed, this quantity is highly coupled with the rheology of granular media. Here, we investigated the performance of the stochastic-optical method (SOM), proposed by [Sarno et al. Granular Matter (2016) 18: 80]. The method works thanks to highly-controlled illumination conditions, guaranteed by a flickering-free planar lamp, and uses a high-speed digital camera. Namely, the indirect estimation of the near-wall volume fraction c3D is made possible by the estimation of a quantity, called two-dimensional volume fraction c2D , which is measurable through an opportune binarization of gray-scale images. With the purpose of assessing the performance of the SOM method on rectangular interrogation windows with different aspect ratios, we present a novel experimental campaign on dispersions of matte-white plastic beads immersed in a dense fluid, where the angle of incidence of light was 25. Moreover, we explored various settings of the binarization algorithm, incorporated in the SOM method. The accuracy of the method is found to be reasonably high with a root-mean-square error on c3D lower than 0.03 for a wide range of settings and independently from the aspect ratio.
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U2 - 10.1088/1742-6596/1249/1/012013
DO - 10.1088/1742-6596/1249/1/012013
M3 - Conference article
AN - SCOPUS:85070020743
SN - 1742-6588
VL - 1249
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - 1
M1 - 012013
Y2 - 29 November 2018 through 30 November 2018
ER -