Suppressing artificial equilibrium states caused by spurious currents in droplet spreading simulations with dynamic contact angle model

Accurate methods for numerical simulation of dynamic wetting and spreading phenomena are a valuable tool to support the advancement of related technological processes such as inkjet-printing. Here, it is demonstrated that numerical methods employing dynamic contact angle models are prone to artificial equilibrium states caused by spurious (parasitic) currents. The capability of different approaches in reducing spurious currents for sessile and spreading droplets with low equilibrium contact angle is evaluated. To minimise the influence of spurious currents on dynamic contact angle models, a smoothing step in the evaluation of the contact line velocity is introduced in this paper. The benefit and performance of this new approach is demonstrated by algebraic volume-of-fluid simulations of spreading and receding droplets with the Kistler dynamic contact angle model