Lattice Boltzmann simulations of contact line motion. I. Liquid-gas systems

Abstract

We investigate the applicability of a mesoscale modeling approach, lattice Boltzmann simulations, to the problem of contact line motion in one and two component, two phase fluids. In this, the first of two papers, we consider liquid-gas systems. Careful implementation of the thermodynamic boundary condition allows us to fix the static contact angle in the simulations. We then consider the behavior of a sheared interface. We show that the contact line singularity is overcome by evaporation or condensation near the contact line which is driven by the curvature of the diffuse interface. An analytic approximation is derived for the angular position of a sheared interface.

Controlling Drop Size and Polydispersity Using Chemically Patterned Surfaces

“…The relaxation time τ tunes the kinematic viscosity via ν = ((∆x) 2 (τ − 1/2))/(3∆t) [31]. The last term in Eq.…”

“…We use a lattice Boltzmann algorithm [31,32,33] to solve the hydrodynamic equations of motion for the drop movement across the patterned substrates thus exploring the key parameters of possible devices. This numerical approach has been shown to agree well with experiments in several cases [1,2,4], giving us confidence in using it for the more complicated situations considered here.…”

Microfluidics of imbibition in random porous media

“…We first consider an inlet-outlet boundary condition. Here, we follow the approach by Briant et al and Zou and He [23,24]. Consider a boundary node situated on the x axis at the inlet of the system in Fig.…”

“…In order for the collision step to retain the correct conservation laws, the first two moments of the equilibrium distribution functions are constrained by [15,23] …”

“…Higher-order moments of f eq j and g eq j were chosen such that the evolution scheme correctly describes the dynamics of a binary fluid [15,23]: …”