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Unsteady‐State Contact Angle Hysteresis During Droplet Oscillation in Capillary Pores: Theoretical Model and VOF Simulation
Author(s) -
Zeng Chao,
Deng Wen,
Wang Lichun
Publication year - 2021
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2020wr027453
Subject(s) - volume of fluid method , mechanics , hysteresis , contact angle , capillary action , drop (telecommunication) , oscillation (cell signaling) , materials science , amplitude , thermodynamics , physics , chemistry , optics , condensed matter physics , telecommunications , breakup , biochemistry , computer science
Contact angle hysteresis (CAH) is a critical phenomenon that could significantly affect the fate of immiscible bubbles/droplets in vadose zones, nonaqueous phase liquid contaminated aquifers, and saline aquifers for CO 2 sequestration in terms of infiltration patterns and residual trapping mechanisms. When external physical impacts such as oscillatory excitation or pulse forcing are applied, it could result in pinned oscillation of droplets due to this CAH or mobilization of pinned droplets. Conventional steady‐state analysis of contact angle could underestimate CAH. As the first time to take unsteady‐state effect into consideration, a hydrodynamic analysis is developed in this study to address the unsteady‐state CAH theoretically, and this hydrodynamic model is also validated against volume‐of‐fluid‐based computational fluid dynamics simulations. It is found that the unsteady‐state CAH of drop can significantly lower the critical acceleration amplitude of excitation to achieve the depinning of contact lines of drops.