Practical kinetic model for hard sphere dynamics

The revised Enskog theory for a classical system of hard spheres provides a unified description of both fluid and crystal states over a wide range of densities and wavelengths. However, practical applications of this theory have been limited to fluid states near equilibrium. We propose here a simpler kinetic model that retains its essential physical and mathematical features, but which admits practical application to complex dynamical phenomena. This is illustrated by a calculation of the rheological properties of the fluid phase under shear flow. Good agreement is obtained in comparison with corresponding Monte Carlo simulation results.