Numerical setup:

• Single species: N_s = 1 and no reaction

• Molecular weight: MW = 21.32 g/mol

• Thermal properties: calorically perfect gas c_p = 1538.22 kJ/kg/K, h_ref = - 6.971 X 10⁶ kJ/kg

• Inviscid calculation

Initial conditions:

• x < 0.05 m: (rho_L, u_L, p_L) = (1.000 kg/m³, 0.0 m/s, 1.0 MPa)

• x >= 0.05 m: (rho_R, u_R, p_R) = (0.125 kg/m³, 0.0 m/s, 0.1 MPa)

Boundary conditions:

• Upstream: rho = rho_L and u = u_L

• Downstream: p = p_R