A many-particle lattice gas model for wave phenomena was developed several years ago at Los Alamos by simulating a count of the number of particles in each cell instead of simulating individual particles. The particles were assumed to move to each of the four neighboring cells with roughly equal probabilities. Propagation by finite differences is achieved by calculating ddU as a weighted neighborhood average of U, which is then added to dU, which in turn is added to U. Scattering Behavior Scattering of sound waves results from judiscious choices of propagation parameters. Each cell can also act as an independently driven source of sound, and has state parameters specifying its behavior as a source. Our approximation to a sound source adds a sinusoidal variation to the acoustic field, as determined by cell parameters for amplitude, period, and phase.
All cells act as sources, but most cells just propagate sound because they have zero amplitude.
If the resulting wavelength is more than a few cell widths, a single source generates circular wave fronts, even on a rectangular grid.