Rotational effect on shock-induced phase transitions of the condensed fluid in the hard-sphere model

The properties of fluid phase transition can be distinctly induced by shock-waves in the hard-sphere model. Typical thermal and dynamic characteristics of the fluid have been described by conditions in the Rankine–Hugoniot (RH) theory based on Euler equations. Due to the strong impact from shock-waves, states of excitation or even phase transition can be detected. However, various factors can influence the jump in the fluid, such as degrees of freedom in molecules. The simple hard-sphere model typically assumes three degrees, neglecting internal freedoms of particles. However, the effect of molecular rotation often plays a significant role under general conditions, influencing fluid phase transition. So, the rotational freedom of molecules has been taken into the thermal equations in this work. The excited state or phase transition of the fluid has been substantiated by using the RH theory, and we have found that internal freedoms of the fluid can have a dramatic effect on the physical properties during phase transition processes.