Assessment of the role of numerical errors in setting contact lines to motion in two-phase flow simulations

The physics of the moving contact line is an active topic of research in fluid dynamics and chemistry, and understanding the problem well has important implications for applications such as coating flows, thin films, microfluidics, and droplet impacts. In this work, we explore the behavior of contact lines from two-phase flow simulations of a Navier-Stokes solver fully coupled with a diffuse-interface model for capturing an interface under finite surface tension. Specifically, we examine conditions in which only static contact angles are set as the boundary condition on a no-slip wall. The role of discretization error and mesh size on creating dynamic contact lines with finite velocity are quantitatively assessed. Our results have implications in consideration of inner-outer models under finite slip length for dynamic contact lines.