Similarity solutions and wave interactions in a rarefied polyatomic gas

The present work describes the development of symmetry analysis for a rarefied polyatomic gas with a focus on the Extended Thermodynamics six independent fields (ET6) model. Rarefied polyatomic gas phenomena in Extended Thermodynamics derive mechanisms for several engineering fields, such as aerospace and mechanical engineering. In this work, symmetry analysis is developed by utilizing the one-dimensional optimal system of the corresponding ET6 model to establish the inequivalence class of group invariant solutions. The model deploys the mass density, the velocity, the absolute temperature, and the dynamics pressure to explicitly derive the transport equations and investigate the evolution of characteristic shock and discontinuity waves. A thorough investigation of the interaction between shock and weak discontinuity waves is presented. It enables complete and specific expressions for the amplitudes of transmitted and reflected waves.