The perfect gas (“perfectGas”) assumptions of an ideal gas simplify the equations assuming that \(C_p\) and \(C_v\) are constant. For the current implementation this results in an EOS that is independent of the gas species. The EOS can be described with only \(\gamma\) and \(R\).
| Input | Definition | Default Value | Argument |
|---|---|---|---|
| \(\gamma\) | \(\gamma = C_p/C_v\) | 1.4 | -gamma |
| \(R\) | \(R = C_p - C_v\) | 287.0 | -Rgas |
Decode State
The decode state function computes the required values to compute fluxes from the Euler conserved variables.
Internal Energy
\(\begin{eqnarray} e = e_t - KE \end{eqnarray}\)
Pressure
\(\begin{eqnarray} p = (\gamma - 1.0) \rho e \end{eqnarray}\)
Speed of Sound
\(\begin{eqnarray} a = \sqrt{\gamma p/\rho} \end{eqnarray}\)
Temperature
The temperature function computes T from \(e_t\), \(\rho\vector{u}\), and \(\rho\).
\[\begin{eqnarray} T = \frac{e}{C_v} \\ C_v = \frac{R}{\gamma -1} \end{eqnarray}\]