CLASSICAL KINETIC-THEORY SIMULATIONS USING SMOOTHED PARTICLE HYDRODYNAMICS

The technique of smoothed particle hydrodynamics (SPH) is used to simu late a variety of three-dimensional systems comprised of elastic spher es contained in a box with perfectly reflecting walls. Particle intera ctions are determined solely by the conservative SPH body forces, from which the potential energy function is derived. This function is foll owed to monitor the conservation of the total energy as various initia l nonequilibrium velocity distributions are quickly randomized by part icle collisions. The resulting equilibrium speed and velocity distribu tions are found to agree with those predicted by kinetic theory. The a lgorithm conserves the total energy to within 0.02%. The pressure exer ted on the box walls and the mean free path between collisions are com parable with those expected for a system of rigid particles. The probl em of two isolated systems that are allowed to mix after an impenetrab le partition is removed is also simulated with acceptable results. Fin ally, the equilibrium spatial distribution of the particles is conside red and a semiemperical relationship derived for this multiply anticor related distribution.