Droplet impingement on a solid surface: Parametrization and asymmetry of dynamic contact angle model

The study of the spreading behavior of droplets impinging on solid surfaces is of importance to applications such as inkjet printing and spray coating. The contact angle is an important parameter that influences the spreading behavior of droplets upon impingement on a solid surface. Computational fluid dynamics simulations studying droplet dynamics require a dynamic contact angle (DCA) model with an appropriate set of parameters to simulate the experimental system of interest. We propose a scheme to parameterize a DCA model and tune its parameters for systems of different levels of wettability. The developed DCA models show the varied response for advancing and receding phases of the droplet motion to emphasize the asymmetric nature of the relation between the contact angle and contact line velocity. These models enable accurate simulation of droplet impingement for a wide range of Weber number (We) and Reynolds number (Re) values. The proposed scheme helps tune the parameters of the DCA model in a systematic and quick manner, thereby enabling one to explore the design space better and also reduce the time to design and develop novel fluids and devices for applications dealing with impinging droplets.