2007/10/19 by J. T. Padding, Johan T. Padding, A. A. Louis +1 · 65 citations
Chemical Engineering · Materials Science · Physics and Astronomy · #Brownian motion #Classical mechanics #Condensed matter physics #Geology #Material Dynamics and Properties #Mechanics #Mesoscopic physics #Physics #Pickering emulsions and particle stabilization #Péclet number #Quantum mechanics #Rheology and Fluid Dynamics Studies #Sedimentation #Thermal #Thermal fluctuations #Thermodynamics #cond-mat.soft
paper · pdf · doi:10.1103/physreve.77.011402
published in Physical Review E 77(1), 011402 (American Physical Society) · 11 pages, 12 figures
arxiv created 2007/10/19 · openalex publication_date 2008/01/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We apply a hybrid molecular dynamics and mesoscopic simulation technique to study the steady-state sedimentation of hard sphere particles for Peclet number (Pe) ranging from 0.08 to 12. Hydrodynamic backflow causes a reduction of the average sedimentation velocity relative to the Stokes velocity. We find that this effect is independent of Pe number. Velocity fluctuations show the expected effects of thermal fluctuations at short correlation times. At longer times, nonequilibrium hydrodynamic fluctuations are visible, and their character appears to be independent of the thermal fluctuations. The hydrodynamic fluctuations dominate the diffusive behavior even for modest Pe number, while conversely the short-time fluctuations are dominated by thermal effects for surprisingly large Pe numbers. Inspired by recent experiments, we also study finite sedimentation in a horizontal planar slit. In our simulations distinct lateral patterns emerge, in agreement with observations in the experiments.