We demonstrate how three-dimensional fluid flow simulations can be car
ried out on the Cellular Automata Machine 8 (CAM-8), a special-purpose
computer for cellular automata computations. The principal algorithmi
c innovation is the use of a lattice gas model with a 16-bit collision
operator that is specially adapted to the machine architecture. It is
shown how the collision rules can be optimized to obtain a low viscos
ity of the fluid. Predictions of the viscosity based on a Boltzmann ap
proximation agree well with measurements of the viscosity made on CAM-
8. Several test simulations of flows in simple geometries-channels, pi
pes, and a cubic array of spheres-are carried out. Measurements of ave
rage flux in these geometries compare well with theoretical prediction
s.