LBM SIMULATION OF A DROPLET DRIPPING DOWN A HOLE

: Numerical simulation of the droplet dripping through a hole which is located on the horizontal plate was studied in the current work. To overcome the numerical instabilities and reach the high density and viscosity ratios Lee’s LBM model was used as a numerical scheme to simulate two-phase flow. Also wettability effect was taken into account by imposing the contact angle between solid-liquid and gas phases using Cahn’s wetting theory. The effects of gravitational acceleration, surface tension, equilibrium contact angle, viscosity ratio, density ratio, and also the geometrical parameters, such as the height and width of the hole, have been investigated, separately. In addition to numerical results, high numerical stability and ease of use in surface tension and contact angle controlling fascinated the authors to model this problem. High numerical stability in capturing the remaining fine particles on the surface and slender strip of a droplet which is passing through the small hole is significant. The results show that gravitational force and adhesion force caused by surface tension, are confronting together in this domain. Enhancing the contact angle more than 90 degree makes the surface, hydrophobic and the droplet will drip under gravitational force. Also increasing the surface tension causes increasing in adhesion force which leads to droplet decay. In this case some parts of the droplet will remain on the surface.

Lattice Boltzmann, Droplet, Contact angle, Archimedes, Ohnesorge