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arXiv · 2406.13387

Boundary conditions alter density and stress fluctuations in shear-thickening suspensions

Meng-Fei Hu·Song-Chuan Zhao
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Abstract

Discontinuous shear thickening (DST) in dense suspensions is accompanied by significant fluctuations in stress at a fixed shear rate. In this work, normal stress fluctuations are shown to have a one-to-one relationship with the formation and dissolution of local high-density regions. Namely, a burst in the force response corresponds to the spontaneous appearance of inhomogeneity. We observe that boundary conditions can significantly alter the spatiotemporal scale of these fluctuations, from short-lived to more sustained and enduring patterns. We estimate the occurrence frequency R and the average intensity Q of individual bursts/inhomogeneity events. The growth of R with the shear rate is the most rapid for the rigid boundary, whereas Q is nonmonotonic with confinement stiffness. Our results indicate that boundary conditions alter the development of inhomogeneity and thus the stress response under shear.

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Meng-Fei Hu, Song-Chuan Zhao. 2024-06-19. Boundary conditions alter density and stress fluctuations in shear-thickening suspensions. https://arxiv.org/abs/2406.13387

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