Finite Element Lattice Boltzmann Simulations of Contact Line Dynamics

TL;DR

This paper introduces a finite element lattice Boltzmann method for simulating contact line dynamics in partially wetting fluids, reducing spurious currents and accurately predicting equilibrium states.

Contribution

It extends off-lattice Boltzmann schemes with a finite element formulation to effectively simulate contact line dynamics.

Findings

Reduces spurious currents at the liquid-vapor interface by two orders of magnitude.

Accurately predicts equilibrium states for moderate contact angles.

Demonstrates the scheme's effectiveness through benchmark experiments.

Abstract

The lattice Boltzmann method has become a standard technique for simulating a wide range of fluid flows. However, the intrinsic coupling of momentum and space discretization restricts the traditional lattice Boltzmann method to regular lattices. Alternative off-lattice Boltzmann schemes exist for both single- and multiphase flows that decouple the velocity discretization from the underlying spatial grid. The current study extends the applicability of these off-lattice methods by introducing a finite element formulation that enables simulating contact line dynamics for partially wetting fluids. This work exemplifies the implementation of the scheme and furthermore presents benchmark experiments that show the scheme reduces spurious currents at the liquid-vapor interface by two orders of magnitude compared to a nodal implementation and allows for predicting the equilibrium states accurately in the range of moderate contact angles.