INTERFACIAL VISCOSITY IN VISCOUS FREE-SURFACE FLOWS - A SAMPLE CASE

This work presents a technique for introducing the surface viscosity terms into the numerical codes employed in the analysis of viscous free surface flows, namely, coating flows. Also, it qualitatively describes the effects produced by the surface viscosity on the interfacial dynamic behavior of an incompressible Newtonian liquid in a steady-state flow. The test problem chosen is the flow occurring in the slot coating process, particularly in the region where one end of a curved free surface (a meniscus) detaches from a stationary solid wall while the other end contacts a moving substrate. The governing equations are solved by the finite element method, and a limited set of computed predictions is presented to illustrate how the surface viscosity affects the flow domain.