Critical to Stagnation Pressure ratio \(\left( {\frac{{{P^*}}}{{{P_0}}}} \right)\) for an expansion process is
1
\(\frac{{{P^*}}}{{{P_0}}} = {\left[ {\frac{2}{{\gamma + 1}}} \right]^{\frac{{2\gamma }}{{\left( {\gamma - 1} \right)}}}}\)
2
\(\frac{{{P^*}}}{{{P_0}}} = {\left[ {\frac{2}{{\gamma + 1}}} \right]^{\frac{{\left( {\gamma + 1} \right)}}{{\left( {\gamma - 1} \right)}}}}\)
3
\(\frac{{{P^*}}}{{{P_0}}} = {\left[ {\frac{2}{{\gamma + 1}}} \right]^{\frac{\gamma }{{\left( {\gamma + 1} \right)}}}}\)
4
\(\frac{{{P^*}}}{{{P_0}}} = {\left[ {\frac{2}{{\gamma + 1}}} \right]^{\frac{\gamma }{{\left( {\gamma - 1} \right)}}}}\)