Droplet dynamics and contact-angle hysteresis

Towards Droplet Dynamics Simulation in Polymer Electrolyte Membrane Fuel Cells: Three-Dimensional Numerical Modeling of Confined Water Droplets with Dynamic Contact Angle and Hysteresis

This work focuses on three-dimensional simulation of the dynamics of droplets with contact–angle hysteresis (CAH). Generally, hysteresis is associated with the pinning of the contact [1] and characterized by receding and advancing contact [2], which are linked to the dewetting and wetting processes, respectively. Taking this into account, an effective treatment for this issue is proposed based on a procedure for calculating the nodal contact–angle within the framework of the enriched finite element/level set method. The proposed numerical model is validated against the previously published experimental data addressing the configuration of a water droplet on a tilted rough hydrophobic surface. In this test, the effect of the contact–line pinning as the underlying mechanism for droplet hysteresis phenomenon is also studied. The model is further employed to simulate a liquid droplet confined in a channel in the presence of air flow.

[1] P. G. de Gennes, “Wetting: statics and dynamics,” Reviews of Modern Physics 57, 827–863 (1985).

[2] L. Gao and T. J. McCarthy, “Contact Angle Hysteresis Explained,” Langmuir 22, 6234–6237 (2006), publisher: American Chemical Society