Generalized hydrodynamics, bulk viscosity, and sound wave absorption and dispersion in dilute rigid molecular gases

Generalized hydrodynamic equations are derived from an irreversible kinetic equation for rigid diatomic molecular gases and applied to extract the bulk viscosity by making use of sound wave absorption and dispersion. As a first application of the generalized hydrodynamic equations for molecular gases, the linearized versions of the generalized hydrodynamic equations are applied to study sound wave absorption and dispersion in molecular gases. The results obtained for sound wave absorption and dispersion with the linearized set yield good agreement with experimental data on nitrogen, hydrogen, deuterium, and HD reported in the literature.