LBM Simulation of a Droplet Dripping Down a Hole

Abstract

ABSTRACT:A droplet dripping through a hole, which is located on a horizontal plate, was simulated in the current work. To overcome the numerical instabilities and accommodate the high density and viscosity ratios, Lee's LBM model was used to simulate the 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 using surface tension and contact angle for 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 passing through a small hole is a significant contribution. The results show that gravitational force and adhesion force caused by surface tension, are opposing forces influencing droplet behaviour. Enhancing the contact angle to more than 90 degrees makes the surface hydrophobic and the droplet will drip under gravitational force. Also increasing the surface tension causes increasing adhesion force, which leads to droplet decay. In this case some parts of the droplet will remain on the surface.

Lattice Boltzmann simulation of water droplet impacting a hydrophobic plate with a cylindrical pore

“…They revealed the mechanisms behind droplet infiltration due to the contribution of the capillary force [9]. Haghani [19] implemented a two-dimensional (2D) lattice Boltzmann (LB) method to simulate the gravity-driven droplet dripping through a hole and proposed four different droplet equilibrium states. They indicated that the droplet impact mechanism needs further investigation, and the simulation domain should be extended to a three-dimensional (3D) configuration to match the realistic situation [19].…”

Three-dimensional simulations of Bingham plastic flows with the multiple-relaxation-time lattice Boltzmann model

“…Despite the adoption of special techniques (Tezduyar, 2001;Tezduyar, Takizawa, Moorman, Wright, & Christopher, 2010) or complex grids (Deng, Mao, Tu, Zhang, & Zhang, 2012) to get round potential inaccuracies, simulations are CONTACT Qi-Cheng Sun qcsun@tsinghua.edu.cn cumbersome, thus prompting the development of a more efficient numerical method for Bingham plastics. The lattice Boltzmann model (LBM) has been a successful substitute for traditional CFD methods in various liquid flows (Haghani, Rahimian, & Taghilou, 2013; C.-H. Lee, Huang, & Chiew, 2015). One of the most popular LBM models is the Bhatnagar-Gross-Krook (BGK) model, in which only one single-relaxation time is used (S. Chen & Doolen, 1998).…”

Lattice Boltzmann simulations on the role of channel structure for reactive capillary infiltration

“…This approach has been gaining popularity for handling hydrodynamic systems out of equilibrium involving complex boundaries and interfacial phenomena. More generally, many applications can be figured out in the incompressible limit, i.e., at low Mach numbers (Ghosh, Patil, Mishra, Das, & Das, 2012;Guiet, Reggio, & Teyssedou, 2011;Haghani, Rahimian, & Taghilou, 2013).…”