Numerical Simulations of Hydrodynamics with a Pair Interaction Automaton in Two Dimensions

We perform numerical experiments with a novel cellularautomaton fluid model. The model has simple pair-interaction rules and works in arbitrarily many dimensions; here we consider the twodimensional case. By observing the smoothing-out of the velocity profile of a shear flow and the relaxation of a shear wave, we measure the kinematic shear viscosity and obtain a value of :::::: 0.5. To demonstrate the fluid-like behavior of our automaton model, we also simulate a flow past an obstacle (von Karman vortex street).