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Title

Parameterization of the nonlocal viscosity kernel for an atomic fluid

Author(s)

Hansen, J. S.;  Daivis, Peter J.;  Travis, Karl P.;  Todd, B. D.

Abstract

In this paper we present results for the wave-vector dependent shear viscosity for a model atomic fluid with short ranged repulsive interactions computed by molecular dynamics simulations. It is shown that the data can be fitted to two different simple functional forms over a large density range, namely, a function composed of two Gaussian terms and a Lorentzian type function with a variable wave-vector exponent. The parameters of both functional forms are found to obey simple density dependencies. While the first functional form has the advantage that the inverse Fourier transform can be found analytically, the Lorentzian type function fits the wave-vector dependence better over the range of wave vectors and densities studied here. The results show that the real space viscosity kernel has a width of 2 to 3 atomic diameters. This means that the generalized hydrodynamic constitutive relation is required if the strain rate varies significantly over this distance, a situation commonly encountered for nanofluidic flows.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Molecular Simulation

Source

Physical Review E: Statistical, Nonlinear, and Soft Matter Physics, Vol. 76, no. 4 (Oct 2007), article no. 041121

Publication year

2007

FOR Code(s)

01 Mathematical Sciences;  02 Physical Sciences;  09 Engineering

Keyword(s)

Fluid dynamics;  Fourier transforms;  Inverse problems;  Molecular dynamics method;  Shear flow;  Viscosity

Publisher

American Physical Society

ISSN

1550-2376

Publisher URL

http://dx.doi.org/10.1103/PhysRevE.76.041121

Copyright

Copyright © 2007 The American Physical Society. The published version of the paper is reproduced here with the kind permission of the publisher.

Additional information

The authors would like to thank the Australian Research Council for supporting this project as a part of a Discovery Grant.

Full text

Peer reviewed