Hyperbolicity Region of a Rational Extended Thermodynamics Model with 14 Moments for a Non-polytropic Gas

Rational extended thermodynamics models are composed by a set of balance laws capable of describing far-from-equilibrium thermodynamic phenomena for rarefied gases. Such equations are usually approximated in the neighbourhood of an equilibrium state with respect to non-equilibrium variables and, for this reason, their hyperbolicity is confined in a domain of the phase space called hyperbolicity region. The present work aims to determine such a domain for a nonpolytropic rarefied gas described by a one-dimensional 14 moment theory with a firstorder approximation. The dependence of the heat capacity on the temperature influences significantly the shape of the hyperbolcity region. The para-H \(_2\) example is presented as a case study.