Smoothed particles hydrodynamics numerical simulations of droplets walking on viscous vibrating liquid

Abstract

We study the phenomenon of the “walking droplet”, by means of numerical fluid dynamics simulations using the smoothed particle hydrodynamics numerical method. This phenomenon occurs when a milli- metric drop is released on the surface of an oil of the same composition, contained in a tank and sub- jected to vertical oscillations of frequency and amplitude very close to the Faraday instability threshold. At appropriate values of the parameters of the system under study, the oil droplet jumps permanently on the surface of the vibrating liquid forming a localized wave-particle system, reminding the behaviour of a wave particle quantum system as suggested by de Broglie. In our study, we made relevant simplifying assumptions, however we observe that the wave-drop coupling is surely obtained. Moreover, the droplet and the wave travel at nearly constant velocity, as observed in experiments. These facts suggest that the phenomenon may occur in many contexts and opens the possibility to study it in an extremely wide range of physical configurations.