Lattice Boltzmann modeling of a gravity-driven sliding droplet under a dynamic wetting regime

• Published in: European journal of mechanics, B, Fluids B, Fluids, 2021-03, Vol.86, p.198-209
• Main Authors: Zhumatay, Nursultan, Kabdenova, Bagdagul, Monaco, Ernesto, Rojas-Solórzano, Luis R.
• Format: Article
• Language: English
• Subjects: Bond number; Contact angle; Lattice Boltzmann; Multiphase flow; Shan–Chen; Sliding droplet
• ISSN: 0997-7546; 1873-7390
• DOI: 10.1016/j.euromechflu.2020.12.008

This work presents the numerical modeling of a sliding droplet on a vertical smooth wall under hydrophobic and hydrophilic conditions using the multiphase Shan–Chen Lattice Boltzmann Model (SC-LBM). The gravitational action above the interfacial force was introduced through the variation of the Bond number and contact angle between droplet, solid surface and surrounding fluid. A critical Bond number, above which the droplet would keep indefinitely deforming, was found for different wettability conditions as well as density and viscosity ratios. The critical Bond number proved to be insensitive to the viscosity ratio (Fluid 1/ Fluid 2, Fluid 1: liquid; Fluid 2: gas), but largely dependent on the density ratio (Fluid 1/ Fluid 2, Fluid 1: liquid; Fluid 2: gas). The present SC-LBM results demonstrate the excellent suitability of the multiphase SC-LBM for the prediction of the dynamic contact angle and reproduction of the continuous droplet deformation and eventual breakup of a sliding droplet subject to gravity force. •Gravity-driven sliding droplet may depict a fragmentation above a critical Bond number.•The sliding droplet may depict a sustained deformation along the time when the system operates above critical Bond number.•Viscosity and density ratios exert significant influence on the value of critical Bond number for a given regime.