On the Kinetic Theory of a Fluid Composed of Rigid Spheres

Abstract
The kinetic theory of a fluid composed of rigid sphere molecules is studied by using the methods of statistical mechanics. It is confirmed that the equation of change for the singlet distribution function has precisely the form originally suggested by Enskog on the basis of intuitive arguments involving an appeal to the notion of forward and inverse collisions. The formal derivation of the hydrodynamical equations of motion for the fluid reveals that the flux tensors for the rigid sphere fluid are of the same general form as those for a fluid composed of molecules which interact according to nonimpulsive forces.