413 citations · 4.5k across the 65 of their papers we have counts for
24 papers · 1 filter
Crystalline and polycrystalline regimes in a periodically sheared 2-dimensional system of disks
Siyuan Su, Jie Zhang, Charles Radin +1
A layer of monodisperse circular steel disks in a nearly square horizontal cell forms, for shear amplitudes SA 0.08, hexagonal close-packed crystallites that grow and merge u…
Homogeneous crystallization in cyclically sheared frictionless grains
Weiwei Jin, Corey S. O'Hern, Charles Radin +2
Many experiments over the past half century have shown that, for a range of protocols, granular materials compact under pressure and repeated small disturbances. A recent experimen…
Phases of granular matter
Charles Radin, Harry L. Swinney
An understanding of homogeneous nucleation of crystalline structure from a disordered medium such as a liquid remains an important unsolved problem in condensed matter physics. Gui…
Nucleation in sheared granular matter
Frank Rietz, Charles Radin, Harry L. Swinney +1
We present an experiment on crystallization of packings of macroscopic granular spheres. This system is often considered to be a model for thermally driven atomic or colloidal syst…
Shearing of frictional sphere packings
Jean-François Métayer, Donald J. Suntrup, Charles Radin +2
We measure shear response in packings of glass beads by pulling a thin, rough, metal plate vertically through a bed of volume fraction phi, which is set, before the plate is pulled…
Onset of Patterns in an Ocillated Granular Layer: Continuum and Molecular Dynamics Simulations
J. Bougie, J. Kreft, J. B. Swift +1
We study the onset of patterns in vertically oscillated layers of frictionless dissipative particles. Using both numerical solutions of continuum equations to Navier-Stokes order a…
Sound speed in water-saturated glass beads as a function of frequency and porosity
Theodore F. Argo, Matthew D. Guild, Preston S. Wilson +3
Sound propagation in water-saturated granular sediments is known to depend on the sediment porosity, but few data in the literature address both the frequency and porosity dependen…
Onset of mechanical stability in random packings of frictional spheres
Melissa Jerkins, Matthias Schröter, Harry L. Swinney +3
Using sedimentation to obtain precisely controlled packings of noncohesive spheres, we find that the volume fraction of the loosest mechanically stable packing is in…
Geometry-induced asymmetric diffusion
Robert S. Shaw, Norman Packard, Matthias Schröter +1
Past work has shown that ions can pass through a membrane more readily in one direction than the other. We demonstrate here in a model and an experiment that for a mixture of small…
Fluidization of a vertically oscillated shallow granular layer
Jennifer Kreft, Matthias Schroeter, Jack B. Swift +1
Molecular dynamics simulations are used to study fluidization of a vertically vibrated, three-dimensional shallow granular layer. As the container acceleration is increased above g…
Phase transition in a static granular system
Matthias Schröter, Sibylle Nägle, Charles Radin +1
We find that a column of glass beads exhibits a well-defined transition between two phases that differ in their resistance to shear. Pulses of fluidization are used to prepare stat…
Mechanisms in the size segregation of a binary granular mixture
M. Schröter, S. Ulrich, J. Kreft +2
A granular mixture of particles of two sizes that is shaken vertically will in most cases segregate. If the larger particles accumulate at the top of the sample, this is called the…
Statistical mechanics of two-dimensional turbulence
Sunghwan Jung, P. J. Morrison, Harry L. Swinney
The statistical mechanical description of two-dimensional inviscid fluid turbulence is reconsidered. Using this description, we make predictions about turbulent flow in a rapidly r…
Velocity difference statistics in turbulence
Sunghwan Jung, Harry L. Swinney
We unify two approaches that have been taken to explain the non-Gaussian probability distribution functions (PDFs) obtained in measurements of longitudinal velocity differences in…
Mach cone in a shallow granular layer
Patrick Heil, E. C. Rericha, Daniel I. Goldman +1
We study the V-shaped wake (Mach cone) formed by a cylindrical rod moving through a thin, vertically vibrated granular layer. The wake, analogous to a shock (hydraulic jump) in sha…
Pattern formation and shocks in granular gases
Harry L. Swinney, E. C. Rericha
Granular media such as sand and sugar are ubiquitous in nature and industry but are less well understood than fluids or solids. We consider the behavior of rapid granular flows whe…
Steady state velocity distributions of an oscillated granular gas
Sung Joon Moon, J. B. Swift, Harry L. Swinney
We use a three-dimensional molecular dynamics simulation to study the single particle distribution function of a dilute granular gas driven by a vertically oscillating plate at hig…
Kink-induced transport and segregation in oscillated granular layers
Sung Joon Moon, Daniel I. Goldman, J. B. Swift +1
We use experiments and molecular dynamics simulations of vertically oscillated granular layers to study horizontal particle segregation induced by a kink (a boundary between domain…
Role of friction in pattern formation in oscillated granular layers
Sung Joon Moon, J. B. Swift, Harry L. Swinney
Particles in granular flows are often modeled as frictionless (smooth) inelastic spheres; however, there exist no frictionless grains, just as there are no elastic grains. Our mole…
Fluctuations and Pinch-Offs Observed in Viscous Fingering
Mitchell G. Moore, Anne Juel, John M. Burgess +2
Our experiments on viscous (Saffman-Taylor) fingering in Hele-Shaw channels reveal several phenomena that were not observed in previous experiments. At low flow rates, growing fing…
Shocks in Vertically Oscillated Granular Layers
J. Bougie, Sung Joon Moon, J. B. Swift +1
We study shock formation in vertically oscillated granular layers, using both molecular dynamics simulations and numerical solutions of continuum equations to Navier-Stokes order.…
Phase Bubbles and Spatiotemporal Chaos in Granular Patterns
Sung Joon Moon, M. D. Shattuck, C. Bizon +3
We use inelastic hard sphere molecular dynamics simulations and laboratory experiments to study patterns in vertically oscillated granular layers. The simulations and experiments r…
Fluctuations in viscous fingering
Mitchell G. Moore, Anne Juel, John M. Burgess +2
Our experiments on viscous (Saffman-Taylor) fingering in Hele-Shaw channels reveal finger width fluctuations that were not observed in previous experiments, which had lower aspect…
Shocks in supersonic sand
E. Rericha, C. Bizon, M. D. Shattuck +1
We measure time-averaged velocity, density, and temperature fields for steady granular flow past a wedge and calculate a speed of granular pressure disturbances (sound speed) equal…