Lattice Gas Cellular Automaton

The HPP/FHP lattice gas: particles hop between lattice sites and collide according to local conservation rules. Macroscopic fluid dynamics emerges from these microscopic Boolean operations — an exact microscopic model of the Navier-Stokes equations.

Particles: — Steps: 0 Density: — Mode: HPP

Model

Initial density0.30

Obstacle

Render

Speed3

HPP (Hardy-Pomeau-Pazzis 1973): 4 velocity directions on square lattice. Mass + momentum conserved per collision. FHP (Frisch-Hasslacher-Pomeau 1986): 6 directions on hexagonal lattice — required for isotropic Navier-Stokes. Lattice gases recover Navier-Stokes in the macroscopic limit despite being fully discrete and reversible at the microscale.