Phase-Field Modeling of Oscillatory Wetting Phenomena with Contact Angle Hysteresis

TR Number
Date
2022-06-02
Journal Title
Journal ISSN
Volume Title
Publisher
Virginia Tech
Abstract

A recently published experimental study by Xia and Steen examines the connection between the contact line velocity and contact angle of liquid drops on an oscillating substrate that display contact angle hysteresis. Of particular interest in this experimental study is the analysis of the dependence of contact angle deviation on contact line velocity. Indeed it is found that for small angular displacements, there is a linear relationship between the two. Moreover, the oscillating drop exhibits contact angle hysteresis that is much greater than that measured from quasi-static experiments. Here we use a phase-field model of dynamic wetting which directly includes the contact angle hysteresis to simulate the results of the aforementioned authors. A thorough derivation of the governing equations is presented, starting from the pioneering work of Cahn and Hilliard. Our model is unique due to the explicit inclusion of contact angle hysteresis, a phenomenon that has proven quite difficult to model. We demonstrate that by choosing appropriate parameters, our model can achieve very good agreement with experimental data. Further, we compare to our results to those computed using another model, further validating our method. We then investigate the effects of contact line friction and the hysteresis window, which are otherwise very difficult to explore experimentally.

Description
Keywords
Fluid Dynamics, FEM, Simulation
Citation
Collections