A new paradigm for treating the singularity in the stress tensor at the contact line

When two fluids incapable of mixing adjoin, a fluid-fluid interface is formed. Where this interface joins a solid surface is the contact line. Much study has been devoted to static contact lines, but dynamic contact line motion has received little attention.

Because the Newtonian shear stress tensor is singular at the contact line, this study attempts to resolve the singularity by using non-equilibrium continuum mechanics. This contact line model includes additional strain rate terms caused by molecular rotation of the fluid particles in the interfacial region. These terms are placed in the angular momentum and energy equations.

This model does indeed resolve the shear stress and shear force singularity at the contact line. The results also compare favorably with a previous contact line study conducted using an ad hoc method with slip boundary conditions (Dussan V., 1976).