Two-phase flows with moving contact lines and surfactant above the critical micelle concentration*

In this work, we present three-dimensional direct numerical simulations of a two-phase moving contact line problem in the presence of surfactants. The model underlying the simulations accounts for surfactant solubility effects and is valid above the critical micelle concentration. The moving contact line model is incorporated using a Generalised Navier Boundary Condition where the viscous stresses along with the surfactant-dependent Young stresses are included. A parametric study is presented for the case of flow past a soil adhering to a substrate in a channel in connection with detergency-type applications. We assess the effects of Marangoni stresses, substrate kinetics near the contact line, and mass-action kinetics between the interface and the substrate that are relevant to cleaning and decontamination.