Viscosity kernel of molecular fluids: Butane and polymer melts

Ruslan Puscasu, Billy Todd, Peter Daivis, Jesper Schmidt Hansen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

The wave-vector dependent shear viscosities for butane and freely jointed chains have been determined. The transverse momentum density and stress autocorrelation functions have been determined by equilibrium molecular dynamics in both atomic and molecular hydrodynamic formalisms. The density, temperature, and chain length dependencies of the reciprocal and real-space viscosity kernels are presented. We find that the density has a major effect on the shape of the kernel. The temperature range and chain lengths considered here have by contrast less impact on the overall normalized shape. Functional forms that fit the wave-vector-dependent kernel data over a large density and wave-vector range have also been tested. Finally, a structural normalization of the kernels in physical space is considered. Overall, the real-space viscosity kernel has a width of roughly 3–6 atomic diameters, which means that generalized hydrodynamics must be applied in predicting the flow properties of molecular fluids on length scales where the strain rate varies sufficiently in the order of these dimensions (e.g., nanofluidic flows).
OriginalsprogEngelsk
TidsskriftPhysical Review E (Statistical, Nonlinear, and Soft Matter Physics)
Vol/bind82
Udgave nummer1
Sider (fra-til)011801
Antal sider15
ISSN1539-3755
DOI
StatusUdgivet - 2010

Citer dette

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abstract = "The wave-vector dependent shear viscosities for butane and freely jointed chains have been determined. The transverse momentum density and stress autocorrelation functions have been determined by equilibrium molecular dynamics in both atomic and molecular hydrodynamic formalisms. The density, temperature, and chain length dependencies of the reciprocal and real-space viscosity kernels are presented. We find that the density has a major effect on the shape of the kernel. The temperature range and chain lengths considered here have by contrast less impact on the overall normalized shape. Functional forms that fit the wave-vector-dependent kernel data over a large density and wave-vector range have also been tested. Finally, a structural normalization of the kernels in physical space is considered. Overall, the real-space viscosity kernel has a width of roughly 3–6 atomic diameters, which means that generalized hydrodynamics must be applied in predicting the flow properties of molecular fluids on length scales where the strain rate varies sufficiently in the order of these dimensions (e.g., nanofluidic flows).",
author = "Ruslan Puscasu and Billy Todd and Peter Daivis and Hansen, {Jesper Schmidt}",
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Viscosity kernel of molecular fluids : Butane and polymer melts. / Puscasu, Ruslan; Todd, Billy; Daivis, Peter; Hansen, Jesper Schmidt.

I: Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Bind 82, Nr. 1, 2010, s. 011801.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Viscosity kernel of molecular fluids

T2 - Butane and polymer melts

AU - Puscasu, Ruslan

AU - Todd, Billy

AU - Daivis, Peter

AU - Hansen, Jesper Schmidt

PY - 2010

Y1 - 2010

N2 - The wave-vector dependent shear viscosities for butane and freely jointed chains have been determined. The transverse momentum density and stress autocorrelation functions have been determined by equilibrium molecular dynamics in both atomic and molecular hydrodynamic formalisms. The density, temperature, and chain length dependencies of the reciprocal and real-space viscosity kernels are presented. We find that the density has a major effect on the shape of the kernel. The temperature range and chain lengths considered here have by contrast less impact on the overall normalized shape. Functional forms that fit the wave-vector-dependent kernel data over a large density and wave-vector range have also been tested. Finally, a structural normalization of the kernels in physical space is considered. Overall, the real-space viscosity kernel has a width of roughly 3–6 atomic diameters, which means that generalized hydrodynamics must be applied in predicting the flow properties of molecular fluids on length scales where the strain rate varies sufficiently in the order of these dimensions (e.g., nanofluidic flows).

AB - The wave-vector dependent shear viscosities for butane and freely jointed chains have been determined. The transverse momentum density and stress autocorrelation functions have been determined by equilibrium molecular dynamics in both atomic and molecular hydrodynamic formalisms. The density, temperature, and chain length dependencies of the reciprocal and real-space viscosity kernels are presented. We find that the density has a major effect on the shape of the kernel. The temperature range and chain lengths considered here have by contrast less impact on the overall normalized shape. Functional forms that fit the wave-vector-dependent kernel data over a large density and wave-vector range have also been tested. Finally, a structural normalization of the kernels in physical space is considered. Overall, the real-space viscosity kernel has a width of roughly 3–6 atomic diameters, which means that generalized hydrodynamics must be applied in predicting the flow properties of molecular fluids on length scales where the strain rate varies sufficiently in the order of these dimensions (e.g., nanofluidic flows).

U2 - 10.1103/PhysRevE.82.011801

DO - 10.1103/PhysRevE.82.011801

M3 - Journal article

VL - 82

SP - 011801

JO - Physical Review E

JF - Physical Review E

SN - 2470-0045

IS - 1

ER -