Complete Operational Equations of State for Hydrocode

Operational equations of state (EOS) can be defined as the EOS that have the form of different operators. For the shock wave and high- pressure communities, the classical example of the operational EOS is the famous Mie-Grüneisen equation. With all its valuable features, the Mie-Grüneisen EOS suffers serious weaknesses as well. In particular, it is thermodynamically inconsistent with various widespread models of the heat capacity functions. In many applications, the heat capacity is assumed constant. This assumption is thermodynamically consistent with the Mie-Grüneisen EOS; however, it does not always provide sufficient flexibility in modeling physical phenomena, e.g., when dealing with polymers. In this paper, we discuss the concept of operational EOS, distinguishing between the complete and incomplete EOS, as well as distinguishing between thermodynamically consistent and inconsistent models. We also suggest some simple examples of the operational EOS that are thermodynamically complete and consistent and can be recommended for modeling shock and blast phenomena.