The flow of an axisymmetric supersonic mixed compression air intake has been simulated numerically in order to investigate the effects and also the necessity of three-dimensional (3D) modeling. For this purpose, the supersonic intake has been simulated numerically via axisymmetric and 3D CFD solver, solving steady state Reynolds-averaged Navier-Stokes equations along with SST k-ω turbulence model, at free-stream Mach number of 2.0 at zero angle of attack. The grid of the 3D cases was a 14.4-degree sector, instead of a 360-degree domain, with rotational periodic boundary condition for side boundaries. The results show that the static and total pressure distribution almost matches well with experimental data for both the axisymmetric and 3D simulations. If the prediction of performance parameters is the main goal of simulations, it seems that axisymmetric simulation presents adequate accuracy and 3D simulation is not a reasonable choice. 3D numerical simulation results in a more detailed study on supersonic intakes, including shock-boundary layer interaction, the location of terminal shock, and consequent separation point. 3D effects in axisymmetric supersonic intakes in axisymmetric flow condition are not enough strong to affect significantly on the intake performance in all operational condition. However, it seems that these effects play a more important role in critical and weak supercritical condition at steady state operation.

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