Ramses van Zon et al 2008 Nonlinearity 21 R119 doi:10.1088/0951-7715/21/5/R01
Ramses van Zon1,3, S S Ashwin2,3 and E G D Cohen3
Show affiliationsRecommended by J R Dorfman
To describe short time (picosecond) and small scale (nanometre) transport in fluids, a Green's function approach was recently developed. This approach relies on an expansion of the distribution of single particle displacements around a Gaussian function, yielding an infinite series of correction terms. Applying a recent theorem (van Zon and Cohen 2006 J. Stat. Phys. 123 1–37) shows that for sufficiently small times the terms in this series become successively smaller, so that truncating the series near or at the Gaussian level might provide a good approximation. In this paper, we derive a theoretical estimate for the time scale at which truncating the series at or near the Gaussian level could be supposed to be accurate for equilibrium nanoscale systems. In order to numerically estimate this time scale, the coefficients for the first few terms in the series are determined in computer simulations for a Lennard-Jones (LJ) fluid, an isotopic LJ mixture and a suspension of a LJ-based model of nanoparticles in a LJ fluid. The results suggest that for LJ fluids an expansion around a Gaussian is accurate at time scales up to a picosecond, while for nanoparticles in suspension (a nanofluid), the characteristic time scale up to which the Gaussian is accurate becomes of the order of 5–10 ps.
61.20.Ja Computer simulation of liquid structure
Issue 5 (May 2008)
Received 31 January 2007
Published 4 April 2008
Ramses van Zon et al 2008 Nonlinearity 21 R119
S Morrison et al 2008 New J. Phys. 10 073032
Z Hao et al 2000 Supercond. Sci. Technol. 13 612
Jan Laufer et al 2007 Phys. Med. Biol. 52 141
Vijay Balasubramanian et al JHEP03(2005)007
S Saxena et al 1986 J. Phys. B: At. Mol. Phys. 19 301
Matt Visser and David L Wiltshire 2004 Class. Quantum Grav. 21 1135
Ulvi Yurtsever 1994 Class. Quantum Grav. 11 999
M Kopycinska-Müller et al 2005 Nanotechnology 16 703
Christiana Athanasiou et al JHEP08(2006)055