The separated flows in a converging-diverging conical nozzle are investigated through numerical simulations for various pressure ratios. To integrate axisymmetric Navier-Stokes equations, we have used AUSM scheme for spatial derivatives and Pulliam`s 2nd order subiteration time stepping method for implicit time integration. Numerical results have revealed that the separated flow structures are rather complex compared to the simple quasi-one dimensional case. Depending on the pressure ratio, the flow within the nozzle is either separated or non-separated. For separated flows, various flow patterns are realized again depending on the pressure ratios.
Typical flow features can be categorized as : steady flow with regular reflection or Mach reflection, unsteady periodic flows alternating between the flow with regular reflection and th flow with Mach reflection, steady flow having Mach reflection with or without recirculation region behind the Mach disk, Unsteady periodic flow having Mach disk with or without recirculation region. The occurrence of these flow types for various pressure ratios based on the computational results and the flow regimes are given in terms of pressure ratios.
