Limitation of the contact angle in the problem of a drop of a liquid on a vibrating substrate

The article deals with the process of fluctuations of a liquid droplet of a small volume lying on a vibrating hydrophobic rigid substrate. The study is carried out by the numerical simulation method of Euler fluid volume (Volume of Fluid — VoF). We study problems of accounting for dynamic changes in the contact angle at the triple point of the liquid-substrate-to-air as well as the impact of changes in the range of the contact angle on the processes that accompany the forced oscillations of the drop. Particular attention is paid to topological features formed in a drop of internal flows. The connection between the interaction of different surface effects, transformation of internal flows, the size limit changes in the contact angle of the substrate and the phase fluctuations are considered in detail. All numerical results are compared with experimental data.