An extended analysis of the viscosity kernel for monatomic and diatomic fluids

Puscasu, R, Todd, B, Daivis, P and Hansen, J 2010, 'An extended analysis of the viscosity kernel for monatomic and diatomic fluids', Journal Of Physics - Condensed Matter, vol. 22, no. 19, pp. 1-12.

Document type: Journal Article
Collection: Journal Articles

Title An extended analysis of the viscosity kernel for monatomic and diatomic fluids
Author(s) Puscasu, R
Todd, B
Daivis, P
Hansen, J
Year 2010
Journal name Journal Of Physics - Condensed Matter
Volume number 22
Issue number 19
Start page 1
End page 12
Total pages 12
Publisher Institute of Physics Publishing Ltd.
Abstract We present an extended analysis of the wavevector dependent shear viscosity of monatomic and diatomic (liquid chlorine) fluids over a wide range of wavevectors and for a variety of state points. The analysis is based on equilibrium molecular dynamics simulations, which involve the evaluation of transverse momentum density and shear stress autocorrelation functions. For liquid chlorine we present the results in both atomic and molecular formalisms. We find that the viscosity kernel of chlorine in the atomic representation is statistically indistinguishable from that in the molecular representation. The results further suggest that the real space viscosity kernels of monatomic and diatomic fluids depend sensitively on the density, the potential energy function and the choice of fitting function in reciprocal space. It is also shown that the reciprocal space shear viscosity data can be fitted to two different simple functional forms over the entire density, temperature and wavevector range: a function composed of n-Gaussian terms and a Lorentzian-type function. Overall, the real space viscosity kernel has a width of 3-6 atomic diameters, which means that the generalized hydrodynamic constitutive relation is required for fluids with strain rates that vary nonlinearly over distances of the order of atomic dimensions.
Keyword(s) atomic diameter
atomic dimension
autocorrelation functions
constitutive relations
equilibrium molecular dynamics
extended analysis
fitting functions
liquid chlorine
molecular representations
reciprocal space
simple functional forms
state points
transverse momenta
wave vector
DOI - identifier 10.1088/0953-8984/22/19/195105
Copyright notice © 2010 IOP Publishing Ltd
ISSN 0953-8984
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Citation counts: TR Web of Science Citation Count  Cited 7 times in Thomson Reuters Web of Science Article | Citations
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