NACA engine inlet CFD (S-duct)

Project · Project 17

A comprehensive CFD study of a NACA-type engine inlet using STAR-CCM+, evaluating aerodynamic performance metrics including total pressure recovery, compressor face distortion, and mass flow rate efficiency under varying angles of attack (0°, 15°, 30°).

Method

The simulation was based on compressible turbulent flow at Mach 0.21 through an S-duct geometry, requiring full setup of the physics models (RANS with both k–ε and k–ω SST closures), boundary conditions, and ideal gas properties.

Custom field functions were developed to compute the key performance parameters directly from the flow solution, including pressure recovery and distortion metrics, enabling quantitative assessment of inlet performance rather than qualitative inspection.

A detailed meshing strategy was implemented using trimmed cells and prism layers, with mesh quality validation on skewness, aspect ratio and y+, plus refinement studies to ensure numerical stability and physical accuracy.

Results

Results showed a clear degradation of inlet performance with increasing angle of attack, with reduced total pressure recovery and increased flow distortion at the compressor face, consistent with aerodynamic expectations.

A model comparison between turbulence closures was also performed, demonstrating improved agreement with experimental data using the k–ω SST model — the expected outcome for a flow dominated by adverse pressure gradients and secondary flow in a curved duct.