*2.2. Constitutive Relations*

The gas-phase constitutive equation is characterized by the effective viscosity of the gas. The solid-phase constitutive relationship is expressed in terms of solid stress. Tables 1 and 2 summarize a detailed description of the constitutive relations [37–42].

**Table 1.** Gas constitutive relations.



**Table 2.** Solid constitutive relations.
