On the transport properties of simple liquids

1986 ◽  
Vol 64 (2) ◽  
pp. 211-214
Author(s):  
S. K. Datta
Keyword(s):  
Shear Viscosity ◽  
Pair Potential ◽  
Viscosity Coefficient ◽  
Simple Fluids ◽  
Jones Potential ◽  
Simple Liquids ◽  
Lennard Jones ◽  
Approximate Nature ◽  
Real Fluids ◽  
Analytical Expressions

Closed analytical expressions for the diffusion coefficient and shear-viscosity coefficient of dense, simple fluids characterized by the Lennard-Jones potential function have been obtained using the Weeks, Chandler, and Andersen criterion for the division of the pair potential. The expressions are then used to calculate these properties for some real fluids. The deviations between the estimated and measured values of the coefficients are attributed mostly to the approximate nature of the Kirkwood and Rice expressions for shear viscosity and the friction coefficient used to calculate those properties.

scholarly journals A Review of Geometry, Construction and Modelling for Carbon Nanotori

2019 ◽  
Vol 9 (11) ◽  
pp. 2301 ◽  
Author(s):  
Pakhapoom Sarapat ◽  
James Hill ◽  
Duangkamon Baowan
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Single Walled Carbon Nanotubes ◽  
Continuum Approximation ◽  
Interaction Energies ◽  
Jones Potential ◽  
Lennard Jones ◽  
Walled Carbon Nanotubes ◽  
Analytical Expressions ◽  
The Continuum

After the discovery of circular formations of single walled carbon nanotubes called fullerene crop circles, their structure has become one of the most researched amongst carbon nanostructures due to their particular interesting physical properties. Several experiments and simulations have been conducted to understand these intriguing objects, including their formation and their hidden characteristics. It is scientifically conceivable that these crop circles, nowadays referred to as carbon nanotori, can be formed by experimentally bending carbon nanotubes into ring shaped structures or by connecting several sections of carbon nanotubes. Toroidal carbon nanotubes are likely to have many applications, especially in electricity and magnetism. In this review, geometry, construction, modelling and possible applications are discussed and the existing known analytical expressions, as obtained from the Lennard-Jones potential and the continuum approximation, for their interaction energies with other nanostructures are summarised.

On the surface tension and shear viscosity of square-well fluids

1981 ◽  
Vol 59 (5) ◽  
pp. 673-677
Author(s):  
S. K. Datta
Keyword(s):  
Surface Tension ◽  
Shear Viscosity ◽  
Spherical Model ◽  
Viscosity Coefficient ◽  
Model Approximation ◽  
Mean Spherical Model ◽  
Square Well ◽  
Experimental Values ◽  
Real Fluids ◽  
Nonpolar Molecules

Closed analytical expressions for the surface tension and the shear viscosity coefficient of a square-well fluid have been obtained using the mean spherical model approximation (MSMA) and the exact hard sphere equation of state given by Carnahan and Stirling. The expressions are then used to calculate these properties for some real fluids. The fair agreement between the calculated and experimental values in the case of several symmetric nonpolar molecules, suggests that the representation of the attractive tail by a square-well potential is a satisfactory one even in the calculation of these complex properties and that the use of MSMA in the elucidation of the equilibrium and transport properties of liquids provides a more or less satisfactory and convenient approach.

EFFECT OF MASS ON SHEAR VISCOSITY OF BINARY FLUID MIXTURE CONFINED TO NANOCHANNELS

2009 ◽  
Vol 08 (06) ◽  
pp. 543-550 ◽  
Author(s):  
ROHAN KAUSHAL ◽  
SUNITA SRIVASTAVA ◽  
K. TANKESHWAR
Keyword(s):  
Shear Viscosity ◽  
Transverse Stress ◽  
Number Density ◽  
Fluid Mixture ◽  
Jones Potential ◽  
Binary Fluid ◽  
Lennard Jones ◽  
Auto Correlation ◽  
Auto Correlation Function ◽  
Lower Molar

Flow of fluid in nanochannel has been studied by evaluating transverse stress auto-correlation function and shear viscosity of the Ar–Kr and isotopic fluid mixture interacting via Lennard Jones potential. The enhancement in viscosity due to confinement has been investigated for different mass ratios and concentration of one of the fluids in a binary fluid mixture. It has been found that at a given number density and temperature, mixing fluid of lower molar weight reduces the enhancement in viscosity and also lower the chances of freezing of liquid near the walls. We have also studied the effect of concentration of two species on the viscosity. It is found that the enhancement in viscosity is less when the concentration of particles with lighter mass increases.

scholarly journals Thermodynamic Scaling of the Shear Viscosity of Lennard-Jones Chains of Variable Rigidity

Liquids ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 96-108
Author(s):  
Stephanie Delage Santacreu ◽  
Hai Hoang ◽  
Samy Khennache ◽  
Guillaume Galliero
Keyword(s):  
Shear Viscosity ◽  
Force Fields ◽  
Coarse Grained ◽  
Molecular Models ◽  
Normal Alkanes ◽  
Lennard Jones ◽  
Simple Alternative ◽  
Points Of View ◽  
Dynamics Simulations ◽  
Real Fluids

In this work, the thermodynamic scaling framework has been used to emphasize the limitations of fully flexible coarse grained molecular models to yield shear viscosity of real liquids. In particular, extensive molecular dynamics simulations have confirmed that, while being reasonable to describe the viscosity of short normal alkanes, the fully flexible Lennard-Jones and Mie chains force fields are inadequate to capture the density dependence of shear viscosity of medium to long alkanes. In addition, it is shown that such a weakness in terms of coarse grained molecular models can be readily quantified by using the thermodynamic scaling framework. As a simple alternative to these force fields, it is demonstrated that the insertion of a variable intramolecular rigidity in the Lennard-Jones chains model exhibits promising results to model medium to long chain-like real fluids from both thermodynamic and viscosity points of view.

scholarly journals Оценки констант электрон-фононной связи графена с металлическими и неметаллическими подложками

2018 ◽  
Vol 60 (4) ◽  
pp. 808
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Covalent Bond ◽  
Orbital Method ◽  
Phonon Interaction ◽  
Jones Potential ◽  
Electron Phonon Interaction ◽  
Dielectric Substrates ◽  
Lennard Jones ◽  
Strong Covalent Bond ◽  
Two Parameters ◽  
Analytical Expressions

AbstractTwo modes of graphene–substrate interaction have been considered: a weak van der Waals bond and a strong covalent bond. The Lennard–Jones potential and Harrison bond-orbital method are used in the former and latter cases, respectively. Analytical expressions for the electron–phonon interaction constants, which contain only two parameters (binding energy E _ B for graphene and a substrate and distance d between them) have been obtained. The constants have been calculated for metallic, semiconductor, and dielectric substrates.

scholarly journals Surface Energy of Curved Surface Based on Lennard-Jones Potential

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 686
Author(s):  
Dan Wang ◽  
Zhili Hu ◽  
Gang Peng ◽  
Yajun Yin
Keyword(s):  
Surface Energy ◽  
Flat Surface ◽  
Convex Surface ◽  
Pair Potential ◽  
Spherical Geometry ◽  
Surface Geometry ◽  
Jones Potential ◽  
Lennard Jones ◽  
Local Principle ◽  
Geometrical Effect

Although various phenomena have confirmed that surface geometry has an impact on surface energy at micro/nano scales, determining the surface energy on micro/nano curved surfaces remains a challenge. In this paper, based on Lennard-Jones (L-J) pair potential, we study the geometrical effect on surface energy with the homogenization hypothesis. The surface energy is expressed as a function of local principle curvatures. The accuracy of curvature-based surface energy is confirmed by comparing surface energy on flat surface with experimental results. Furthermore, the surface energy for spherical geometry is investigated and verified by the numerical experiment with errors within 5%. The results show that (i) the surface energy will decrease on a convex surface and increase on a concave surface with the increasing of scales, and tend to the value on flat surface; (ii) the effect of curvatures will be obvious and exceed 5% when spherical radius becomes smaller than 5 nm; (iii) the surface energy varies with curvatures on sinusoidal surfaces, and the normalized surface energy relates with the ratio of wave height to wavelength. The curvature-based surface energy offers new insights into the geometrical and scales effect at micro/nano scales, which provides a theoretical direction for designing NEMS/MEMS.

Investigation of the density dependence of the shear relaxation time of dense fluids

2005 ◽  
Vol 83 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Mehrdad Bamdad ◽  
Saman Alavi ◽  
Bijan Najafi ◽  
Ezat Keshavarzi
Keyword(s):  
Relaxation Time ◽  
Shear Modulus ◽  
Density Dependence ◽  
Radial Distribution ◽  
Shear Viscosity ◽  
Viscosity Coefficient ◽  
Dense Fluids ◽  
Lennard Jones ◽  
Shear Relaxation ◽  
Shear Relaxation Time

The shear relaxation time, a key quantity in the theory of viscosity, is calculated for the Lennard–Jones fluid and fluid krypton. The shear relaxation time is initially calculated by the Zwanzig–Mountain method, which defines this quantity as the ratio of the shear viscosity coefficient to the infinite shear modulus. The shear modulus is calculated from highly accurate radial distribution functions obtained from molecular dynamics simulations of the Lennard–Jones potential and a realistic potential for krypton. This calculation shows that the density dependence of the shear relaxation time isotherms of the Lennard–Jones fluid and Kr pass through a minimum. The minimum in the shear relaxation times is also obtained from calculations using the different approach originally proposed by van der Gulik. In this approach, the relaxation time is determined as the ratio of shear viscosity coefficient to the thermal pressure. The density of the minimum of the shear relaxation time is about twice the critical density and is equal to the common density, which was previously reported for supercritical gases where the viscosity of the gas becomes independent of temperature. It is shown that this common point occurs in both gas and liquid phases. At densities lower than this common density, even in the liquid state, the viscosity increases with increasing temperature.Key words: dense fluids, radial distribution function, shear modulus, shear relaxation time, shear viscosity.

Sign in / Sign up

Export Citation Format

Share Document