Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions

Abstract

The effect of interfacial slip on steady-state and time-periodic flows of monatomic liquids is investigated using non-equilibrium molecular dynamics simulations. The fluid phase is confined between atomically smooth rigid walls, and the fluid flows are induced by moving one of the walls. In steady shear flows, the slip length increases almost linearly with shear rate. We found that the velocity profiles in oscillatory flows are well described by the Stokes flow solution with the slip length that depends on the local shear rate. Interestingly, the rate dependence of the slip length obtained in steady shear flows is recovered when the slip length in oscillatory flows is plotted as a function of the local shear rate magnitude. For both types of flows, the friction coefficient at the liquid-solid interface correlates well with the structure of the first fluid layer near the solid wall.

Nonequilibrium molecular dynamics simulations of nanoconfined fluids at solid-liquid interfaces

“…The last two terms disappear in the directions which define the shear plane. 39 In these directions, Newton's equations are solved. By applying the Langevin thermostat, every particle is coupled to a viscous background and a stochastic heat bath.…”

“…The fluid velocity at the solid-fluid interface is usually quantified by the slip length L s , which is defined through 18,23,39 …”

Rheology and morphology of no-slip sheared polymer nanocomposite under creep condition

“…For example, it is well recognized that fluid flows in confined systems can be significantly affected by slip or no-slip boundary conditions (NBSCs) and the velocity discontinuity near the liquid-solid interface of fluid. 26 Therefore, the nonlinear responses of shear rate and velocity profile of non-Newtonian fluids 26 are a sizable challenge in these simulations. Therefore, investigations have been done to use an appropriate boundary condition, such as the no-slip boundary condition, to generate a realistic velocity profile in the fluid.…”

Fluid flow through porous and nanoporous media within the prisme of extended thermodynamics: emphasis on the notion of permeability

“…It is well recognized that in nanopores, the no-slip condition is no longer valid. Here, we will substitute it by the following second-order slip boundary condition at = (e.g Priezjev andTroian (2006), Priezjev (2013), Yong and Zhang (2013), Manjare et al (2014), Cherevko and Kizilov (2017)). Similarly, slip boundary conditions were also introduced by Lebon (2014) and Sellitto et al (2016) in their study of heat transport at nanoscales.…”