Modified kinetic theory applied to the shear flows of granular materials
Here, granular materials are characterized by large collections of discrete particles, where the particleparticle interactions are significantly more important than the particlefluid interactions. The current kinetic theory captures fairly accurately the granular flow behavior in the dilute case, when only binary interactions are significant, but is not accurate at all in the dense flow regime, where multiparticle interactions and contacts must be modeled. To improve the kinetic theory results for granular flows in the dense flow regime, we propose a Modified Kinetic Theory (MKT) model that utilizes the contact duration or cutoff time to account for the complex particleparticle interactions in the dense regime. The contact duration model, also called TC model, is originally proposed by Luding and McNamara to solve the inelastic collapse issue existing in the Inelastic Hard Sphere (IHS) model. This model defines a cutoff time t _{c} such that dissipation is not counted if the time between two consecutive contacts is less than t _{c}. As shown in their study, the use of a cutoff time t _{c} can also reduce the dissipation during multiparticle contacts. In this paper we relate the TC model with the Discrete Element Method (DEM) by choosing the cutoff time tmore »
 Authors:

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 Univ. of Texas at San Antonio, San Antonio, TX (United States)
 Texas Christian Univ., Fort Worth, TX (United States)
 Univ. of Texas at El Paso, El Paso, TX (United States)
 Publication Date:
 Grant/Contract Number:
 FE0011453
 Type:
 Accepted Manuscript
 Journal Name:
 Physics of Fluids
 Additional Journal Information:
 Journal Volume: 29; Journal Issue: 4; Journal ID: ISSN 10706631
 Publisher:
 American Institute of Physics
 Research Org:
 Univ. of Texas at San Antonio, San Antonio, TX (United States)
 Sponsoring Org:
 USDOE Office of Fossil Energy (FE)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE; kinetic theory; granular flows modeling; discrete element method
 OSTI Identifier:
 1347615
 Alternate Identifier(s):
 OSTI ID: 1361806
Duan, Yifei, Feng, Zhi Gang, Michaelides, Efstathios E., and Mao, Shaolin. Modified kinetic theory applied to the shear flows of granular materials. United States: N. p.,
Web. doi:10.1063/1.4979632.
Duan, Yifei, Feng, Zhi Gang, Michaelides, Efstathios E., & Mao, Shaolin. Modified kinetic theory applied to the shear flows of granular materials. United States. doi:10.1063/1.4979632.
Duan, Yifei, Feng, Zhi Gang, Michaelides, Efstathios E., and Mao, Shaolin. 2017.
"Modified kinetic theory applied to the shear flows of granular materials". United States.
doi:10.1063/1.4979632. https://www.osti.gov/servlets/purl/1347615.
@article{osti_1347615,
title = {Modified kinetic theory applied to the shear flows of granular materials},
author = {Duan, Yifei and Feng, Zhi Gang and Michaelides, Efstathios E. and Mao, Shaolin},
abstractNote = {Here, granular materials are characterized by large collections of discrete particles, where the particleparticle interactions are significantly more important than the particlefluid interactions. The current kinetic theory captures fairly accurately the granular flow behavior in the dilute case, when only binary interactions are significant, but is not accurate at all in the dense flow regime, where multiparticle interactions and contacts must be modeled. To improve the kinetic theory results for granular flows in the dense flow regime, we propose a Modified Kinetic Theory (MKT) model that utilizes the contact duration or cutoff time to account for the complex particleparticle interactions in the dense regime. The contact duration model, also called TC model, is originally proposed by Luding and McNamara to solve the inelastic collapse issue existing in the Inelastic Hard Sphere (IHS) model. This model defines a cutoff time tc such that dissipation is not counted if the time between two consecutive contacts is less than tc. As shown in their study, the use of a cutoff time tc can also reduce the dissipation during multiparticle contacts. In this paper we relate the TC model with the Discrete Element Method (DEM) by choosing the cutoff time tc to be the duration of contact calculated from the linearspringdashpot softsphere model of the DEM. We examine two types of granular flows: simple shear flow and the plane shear flow, and compare the results of the classical Kinetic Theory (KT) model, the present MKT model, and the DEM model. Here, we show that the MKT model entails a significant improvement over the KT model for simple shear flows at inertial regimes. With the MKT model the calculations are close to the DEM results at solid fractions as high as 0.57. Even for the plane shear flows, where shear rate and solid fraction are inhomogeneous, the results of the MKT model agree very well with the DEM results.},
doi = {10.1063/1.4979632},
journal = {Physics of Fluids},
number = 4,
volume = 29,
place = {United States},
year = {2017},
month = {4}
}