Viscosity of confined inhomogeneous nonequilibrium fluids

2020-02-19 10:58:24

model flow viscosity dependent inhomogeneous

责任者: Junfang Zhang;Todd, B.D.;Travis, K.P. 单位: Centre for Molecular Simulation, Swinburne Univ. of Technol., Hawthorn, Vic., Australia 来源出处: Journal of Chemical Physics(J. Chem. Phys. (USA)),2004/12/01,121(21):10778-86 摘要: We use the nonlocal linear hydrodynamic constitutive model, proposed by Evans and Morriss [Statistical Mechanics of Nonequilibrium Liquids (Academic, London, 1990)], for computing an effective spatially dependent shear viscosity of inhomogeneous nonequilibrium fluids. The model is applied to a simple atomic fluid undergoing planar Poiseuille flow in a confined channel of several atomic diameters width. We compare the spatially dependent viscosity with a local generalization of Newtons law of viscosity and the Navier-Stokes viscosity, both of which are known to suffer extreme inaccuracies for highly inhomogeneous systems. The nonlocal constitutive model calculates effective position dependent viscosities that are free from the notorious singularities experienced by applying the commonly used local constitutive model. It is simple, general, and has widespread applicability in nanofluidics where experimental measurement of position dependent transport coefficients is currently inaccessible. In principle the method can be used to predict approximate flow profiles of any arbitrary inhomogeneous system. We demonstrate this by predicting the flow profile for a simple fluid undergoing planar Couette flow in a confined channel of several atomic diameters width 关键词: channel flow;Couette flow;hydrodynamics;Navier-Stokes equations;nonequilibrium flow;Poiseuille flow;shear flow;viscosity;confined inhomogeneous nonequilibrium fluid viscosity;nonlocal linear hydrodynamic constitutive model;spatially dependent shear viscosity;atomic fluid;planar Poiseuille flow;confined channel;Newton law local generalization viscosity;Navier-Stokes viscosity;notorious singularities;nanofluidics;position dependent transport coefficients;flow profile;planar Couette flow