Capillary effects

Capillary effects in a lattice gas simulation of inmiscible liquids is easily achieved by giving the obstacles and walls a "color" property, in the same way that different particles in the simulation have color.

The character of the obstacles is given by a paramter Pc that makes the obstacles be blue- to red-philic, depending on its value between [0-1]. This probability chooses the color of seven "particles" within an obstacles that only enter in the calculation of the q.F color interaction. In this way, "blue" walls would make for a system that has obstacles blue-philic, and vice versa. A value of 0.5 for the obstacle color probability will make the obstacle "neutral" to either liquid.

The following example simulations use a lattice gas simulation with inmiscible two-type particles. The lattice size is 512x64, with a 50% particle occupancy on a seven-particle FHP III model. The initial configuration is a split red-blue system and the interactions are given by a q.F, where q is the color flux and F is the flux field. The boundary conditions are of an open tube in which the liquids are at rest, i.e. no driving dynamics, with Fermi-Dirac occupancy (u=0). The three example simulations where run for approximately 1000 time steps.

(Click to enlarge)
Blue-philic (Pc=0.0) Neutral (Pc=0.5) Red-philic (Pc=1.0)