Numerical study of wetting stability and sliding behavior of liquid droplets on microgrooved surfaces

3D droplet models are developed to numerically investigate the droplet stability and hysteresis of the three-phase contact line on both horizontal and inclined microgrooved solid surfaces. A numerical method is applied to study the shapes and energies of liquid droplets, with a particular focus on the stability of the suspended wetting state. A normalized form of droplet energy is used to compare the relative stabilities of multiple metastable wetting states and a numerical approach is found to reliably predict the wetting stability of droplets on horizontal microgrooved substrates. For wetting on inclined surfaces, numerical simulations of sliding behavior of liquid droplets on flat and periodic microgrooved surfaces with a range of groove geometry are conducted. A numerical model capable of predicting the critical sliding angle of the drop from the knowledge of advancing and receding angles is developed. The effects of microgroove topography, droplet size, and inclination angle on the droplet dynamic behavior are analyzed. Droplet shape and critical sliding angle, obtained from the numerical models, are compared with those of experimental results and are found to be in very good agreement. Graphical abstract