The moving contact line problemWhen two immiscible fluids are placed on a substrate, the line where the interface of the two fluids intersects the solid substrate is called the contact line. The equilibrium configuration of the static contact line is described by the Young's relation which relates the three coefficients of interfacial tension to the contact angle formed by the fluid-fluid interface with the solid surface. The moving contact line problem, however, has for many years remained an issue of controversy and debate. The main difficulty stems from the fact that classical hydrodynamic equations coupled with the conventional no-slip boundary condition predicts a singularity for the stress that results in a non-physical divergence for the energy dissipation rate. Recently, we systematically investigated the physical processes near a moving contact line using molecular dynamics. Based on the molecular dynamics study, continuum theory and multiscale techniques, we formulated simple and effective continuum models. These models not only remove the non-physical singularities, but also give a faithful description of the physical process near the moving contact line .
WEIQING REN Last modified: Thur Oct 15 20:55:34 EST 2015