Numerical analysis of an adhering droplet applying an adapted feedback deceleration technique

• Published in: International journal of multiphase flow Vol. 145; p. 103808
• Main Authors: Krämer, Veronika, Barwari, Beawer, Burgmann, Sebastian, Rohde, Martin, Rentschler, Simon, Holzknecht, Christopher, Gmelin, Christoph, Janoske, Uwe
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2021
• Subjects: Contact angle hysteresis; Contact line; Critical inclination angle; Critical velocity; Droplet movement; Feedback deceleration technique; Critical inclination angle; Contact angle hysteresis; Feedback deceleration technique; Critical velocity; Droplet movement; Contact line
• ISSN: 0301-9322; 1879-3533
• DOI: 10.1016/j.ijmultiphaseflow.2021.103808

•A VOF-based method to implement the contact angle hysteresis is presented.•A modification for the Feedback Deceleration Technique is introduced and validated.•Input parameters for the new model consist only of fluid and material properties.•The new method reproduces droplet pinning according to existing experimental data.•Numerical results provide an insight in the flow structures inside the droplet. The wetting phenomena and the dynamics of a droplet moved by external forces are essential for many technical applications. However, its numerical modeling has been a challenge and a subject of several investigations in recent years. The objective of the current numerical study is to provide a numerical model within the volume of fluid method that accurately predicts droplet adhesion and the onset of the droplet motion for a three-dimensional droplet. The presented numerical calculations are performed with OpenFOAM® using a multiphase solver hysteresisInterFoam, which is based on widely used solver interFoam and additionally extended by a contact angle hysteresis algorithm. The hysteresis implementation is performed by means of the feedback deceleration technique (FDT) which controls the movement of the contact line. Basically, the current study focuses on determining the suitable control parameter for the modified FDT and its dependency on the examined material system. Finally, the new method is validated for droplets under shear flow as well as on an inclined surface. Different droplet volumes, fluid viscosities and solid surfaces were examined. The numerical results agree well with the experimental data. Besides, the new methodology allows to gain new insights into the inner flow of the droplet.