Numerical Evaluation of Morphing Busemann Inlet at Off-Design Angle of Attack

The performance of inward-turning scramjet inlets degrades at changes in angle of attack, limiting the potential maneuverability of vehicles that could use such inlets. The performance of a baseline, axisymmetric, inward-turning, truncated Busemann-style inlet designed for Mach 6 is characterized at off-design angles of attack using a Reynolds-averaged Navier–Stokes methodology, demonstrating the propensity to unstart. A morphing strategy is proposed in which the same inlet is bent near the throat to face the oncoming freestream as the angle of attack changes. The inlet-isolator performance for the morphed geometry at off-design angles of attack is shown to have substantially improved relative to the baseline. Performance metrics include total pressure recovery, flow distortion, and stream thrust. Grid insensitive solutions are obtained at each angle of attack using a systematic grid adaptation strategy. Susceptibility to unstart due to backpressure is also characterized for the baseline and morphed inlets.