FLUID-DYNAMICAL APPROXIMATION TO THE BOLTZMANN-EQUATION AT THE LEVEL OF THE NAVIER-STOKES EQUATION

The compressible and heat-conductive Navier-Stokes equation obtained as the second approximation of the formal Chapman-Enskog expansion is investigated on its relations to the original nonlinear Boltzmann equation and also to the incompressible Navier-Stokes equation. The solutions of the Boltzmann equation and the incompressible Navier-Stokes equation for small initial data are proved to be asymptotically equivalent (mod decay rate t-5/4) as t→+∞ to that of the compressible Navier-Stokes equation for the corresponding initial data. © 1979 Springer-Verlag.