Simulation of Droplet Flows Using Lattice Boltzmann Method

In this work, the mesoscale approach of two-dimensional lattice Boltzmann method (LBM) has been employed to study droplet collision with a dry wall. The impact of drops with solid walls is simulated by using the pseudo-potential method of LBM. Simulations have been conducted for 2<We<162, and it is shown that the maximum spreading of the drop on the solid surface depends on the surrounding density, velocity of impact, surface tension, and the surface wetting characteristics. For a short time interval right after the impact the spreading diameter is shown to follow a parabolic dependence with time. The spread factor is seen to be higher as the Weber number increases. Under certain conditions when the drop has a high impact velocity and/or low surface tension, the kinetic energy of impact dominates over the dissipation and surface energy, leading to breakup of the drop into smaller drops. This breakup is shown to depend upon the wetting/non-wetting nature of the surface used. The spread factor is found to be a maximum at the time of breakup.