Velocity profiles and energy fluctuations in simple shear granular flows--颗粒学报PARTICUOLOGY

Liu, C., Sun, Q., & Zhou, G. G. D. (2016). Velocity profiles and energy fluctuations in simple shear granular flows. Particuology, 27, 80-87. https://doi.org/10.1016/j.partic.2015.06.003

Velocity profiles and energy fluctuations in simple shear granular flows

Chuanqi Liu ^a, Qicheng Sun ^a *, Gordon G.D. Zhou ^b

a State Key Laboratory for Hydroscience and Engineering, Tsinghua University, Beijing 100084, China
b Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China

10.1016/j.partic.2015.06.003

Volume 27, August 2016, Pages 80-87

Received 21 April 2015, Revised 26 May 2015, Accepted 22 June 2015, Available online 21 October 2015, Version of Record 14 June 2016.

E-mail: qcsun@tsinghua.edu.cn

Highlights

• Simple shear flows in 3D under constant confining pressure were simulated using DEM.

• The model was validated by checking the simulation results against the constitutive laws.

• The dynamic properties (e.g. force chains, velocity profiles) were discussed.

• The mean energy density ratio can work as the criterion to distinguish flow regimes.

Abstract

Rheology analysis of granular flows is important for predicting geophysical hazards and designing industrial processes. Using a discrete element method, we simulate simple shear flows in 3D under a constant confining pressure of 10 kPa. The inertial number proposed by the GDR MiDi group in France is adopted to distinguish rheology regimes. Both translational and angular velocity profiles are investigated, and both fluid-like and solid-like behavior modes are observed in the flows. The maximum angular velocity occurs near the localized deformation area. We also investigate the energy characteristics of the flows and find that at very small shearing speed, the mean kinetic energy density e_k is close to zero, while the mean elastic energy density e_c is much greater. At large shearing speed, e_k increases. The fluctuating parts of the two types of energy increase with increasing shear speed. Thus, the mean energy density ratio e_k/e_c can be used in addition to the inertial number to distinguish flow regimes. These results provide insights from energetics into the rheological properties of granular flows.

Graphical abstract

Keywords

Dense granular flows; Simple shear; Energy fluctuations

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