Granular dynamics and gravity

Abstract

The role of gravity on the dynamics of granular particles is examined via their velocity distributions. Acceleration due to gravity, particle number and the coefficient of restitution have all been...

Rheology of a granular system with capillary interactions

“…Units of σ = m = Θ(t = 0) = 1, where σ is the particle diameter, m is the particle mass and Θ(t) is the mean kinetic energy per particle at time t, were used. The following equation of motion was used [3,12]:…”

“…In particular, granular systems differ sharply from their colloidal analogues in terms of their dynamics, largely due to dissipative collisions; for instance, granular systems often exhibit non-Maxwell-Boltzmann speed distributions [3,[7][8][9][10][11][12], as well as highly spatially inhomogeneous kinetic energies [3][4][5][12][13][14][15]. Studies of the rheological properties of granular systems have mostly focussed on bulk responses such as net flows in response to external forces [6,16,17] rather than on individual particle behaviour.…”

Rotational and translational dynamics and rheology in a granular system

“…The same scale is used for both to facilitate comparison. The solid lines in the top figure are fits to a modified version of Haff's Law[33,41] (K tr (t) = (K i − K ∞ ) / (1 + t/τ H ) 2 + K ∞ ,where K i and K ∞ are the characteristic values at short times and long times respectively, and τ H is a characteristic time; for our experiments, τ H ∼ 4 s.). The inset shows the data and the fits at short times.…”