Traffic and granular flow: the role of data and technology in the understanding of particle dynamics

This is a survey of the interesting phenomenology and the prominent regimes of granular flow, followed by a unified mathematical synthesis of continuum modeling. The unification is achieved by means of “parametric” viscoelasticity and hypoplasticity based on elastic and inelastic potentials. Fully nonlinear, anisotropic viscoelastoplastic models are achieved by expressing potentials as functions of the joint isotropic invariants of kinematic and structural tensors. These take on the role of evolutionary parameters or “internal variables,” whose evolution equations are derived from the internal balance of generalized forces. The resulting continuum models encompass most of the mechanical constitutive equations currently employed for granular media. Moreover, these models are readily modified to include Cosserat and other multipolar effects. Several outstanding questions are identified as to the contribution of parameter evolution to dissipation; the distinction between quasielastic and inelastic models of material instability; and the role of multipolar effects in material instability, dense rapid flow, and particle migration phenomena.

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Numerical simulations of dense granular flow in a two-dimensional channel: The role of exit position

Chinese Physics B ◽

10.1088/1674-1056/27/12/124704 ◽

2018 ◽

Vol 27 (12) ◽

pp. 124704

Author(s):

Tingwei Wang ◽

Xin Li ◽

Qianqian Wu ◽

Tengfei Jiao ◽

Xingyi Liu ◽

...

Keyword(s):

Numerical Simulations ◽

Granular Flow ◽

Two Dimensional ◽

Dense Granular Flow

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The role of particle collisions in pneumatic transport

Journal of Fluid Mechanics ◽

10.1017/s0022112091003427 ◽

1991 ◽

Vol 231 ◽

pp. 345-359 ◽

Cited By ~ 149

Author(s):

M. Y. Louge ◽

E. Mastorakos ◽

J. T. Jenkins

Keyword(s):

Granular Flow ◽

Turbulent Energy ◽

Particle Phase ◽

Particle Collisions ◽

Governing Equations ◽

Vertical Pipe ◽

Fully Developed Flow ◽

Energy Profiles ◽

Balance Of Forces

We analyse the dilute, steady, fully developed flow of relatively massive particles in a turbulent gas in the context of a vertical pipe. The idea is that the exchange of momentum in collisions between the grains and between the grains and the wall plays a significant role in the balance of forces in the particle phase. Consequently, the particle phase is considered to be a dilute system of colliding grains, in which the velocity fluctuations are produced by collisions rather than by the gas turbulence. The balance equations for rapid granular flow are modified to incorporate the drag force from the gas, and boundary conditions, based on collisional exchanges of momentum and energy at the wall, are employed. The turbulence of the gas is treated using a one-equation closure. A numerical solution of the resulting governing equations provides velocity and turbulent energy profiles in agreement with the measurements of Tsuji et al. (1984).

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