Close-packed granular clusters: Hydrostatics and persistent Gaussian fluctuations

Baruch Meerson, Manuel Díez-Minguito, Thomas Schwager, Thorsten Pöschel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Dense granular clusters often behave like macro-particles. We address this interesting phenomenon in a model system of inelastically colliding hard disks inside a circular box, driven by a thermal wall at zero gravity. Molecular dynamics simulations show a close-packed cluster of almost circular shape, weakly fluctuating in space and isolated from the driving wall by a low-density gas. The density profile of the system agrees very well with the azimuthally symmetric solution of granular hydrostatic equations employing constitutive relations by Grossman et al., whereas the widely used Enskog-type constitutive relations show poor accuracy. We find that fluctuations of the center of mass of the system are Gaussian. This suggests an effective Langevin description in terms of a macro-particle, confined by a harmonic potential and driven by delta-correlated noise. Surprisingly, the fluctuations persist when increasing the number of particles in the system.

Original languageAmerican English
Pages (from-to)21-27
Number of pages7
JournalGranular Matter
Issue number1
StatePublished - Dec 2007


  • Granular cluster
  • Granular hydrodynamics
  • Strong fluctuations


Dive into the research topics of 'Close-packed granular clusters: Hydrostatics and persistent Gaussian fluctuations'. Together they form a unique fingerprint.

Cite this