The shock tube study in extended thermodynamics

In this paper we investigate the shock tube experiment with extended thermodynamics. Extended thermodynamics (ET) provides dissipative field equations for monatomic gases which are symmetrically hyperbolic. The theory relies on the extension of the set of variables in order to describe extreme nonequilibrium processes. As an example for such a process we focus on the start-up phase of the shock tube experiment. We show numerically that ET succeeds to describe this short time behavior. For small times more and more variables are needed for a physically valid description. In the limit of very small times the solution of ET for the start-up phase converges to the solution of the free-flight-equation. Additionally it turns out that the system of Navier-Stokes and Fourier fails to describe the start-up phase of a shock tube even qualitatively. (C) 2001 American Institute of Physics.