Shock-wave structure in non-polar diatomic and polyatomic dense gases under rotation and vibration

Abstract

This study investigates the effect of rotation and vibration on the structure of shock waves in moderately dense diatomic and polyatomic non-polar gases using the one-temperature Navier–Stokes–Fourier approach. The modified Enskog equation of state of the gas is taken to include the denseness and shielding effects. The specific heat at constant volume has been taken to be temperature-dependent. The shear viscosity, the bulk viscosity, and the thermal conductivity have been assumed to follow the temperature-dependent power-law model. Nitrogen and oxygen gas have been taken as the test cases for diatomic gases while carbon dioxide was taken for the polyatomic gases. The implicit system of equations is derived and solved numerically for density and temperature. The inclusion of denseness, rotational, and vibrational modes of molecular motion have a significant effect on the density and temperature profiles, the inverse shock thickness, the bulk to shear viscosity ratio, and the molar specific heat at constant pressure. The gas having a low characteristic vibrational temperature has been found to have a high value of inverse shock thickness. The inverse shock thickness, the bulk to shear viscosity ratio, and the molar specific heat at constant pressure for nitrogen and carbon dioxide are found to be in good agreement with the experimental values.