Dynamic contact angle modeling for simulations of drop impingement and sliding

Contact angle physics play a critical role in applications ranging from tissue engineering, pharmaceuticals, aerospace engineering, and flexible electronics (Karim J. Appl. Phys. 2022). This work incorporates sub-grid contact line dynamics into drop-resolved simulations by utilizing dynamic contact angle models, which differ from static contact angle models in that they two-way-couple the contact angle with the resolved velocity field. An anisotropic dynamic contact angle boundary condition inspired by the Cox-Voinov-Tanner model as presented in (LeGrand et. al. J. Fluid Mech. 2005) is developed and imposed into a Navier-Stokes solver with phase field methods.

Model performance is then quantitatively evaluated using two sets of canonical experiments: droplet sliding down an inclined plane (LeGrand et. al. J. Fluid Mech. 2005) and droplet impingement on a flat plate (Yan et. al. J. Eng. Math. 2024). For each test case, the resulting contact angle evolution, droplet dimensions, and velocities are quantitatively compared among a dynamic model simulation, static model simulation, and the experiment. The dynamic model exhibits improved agreement with experimental results, highlighting the importance of incorporating contact line physics into high-fidelity simulations.