NUMERICAL STUDY OF THE PERFORMANCE OF SWEPT, CURVED COMPRESSION SURFACE SCRAMJET INLETS

A computational performance enhancement study was performed employing systematic modifications to a planar-sidewall compression scramjet inl et operating at an entrance Math number of 4 and at a dynamic pressure of 2040 psf. The variations included modifying the planar-sidewall co mpression angle as a function of height, utilizing sidewall curvature, and employing, simultaneously, both forward-swept and reverse-swept c ompression surfaces. Turbulent flowfield solutions were generated by s olving the Reynolds-averaged Navier-Stokes equations to obtain inlet p erformance parameters such as total-pressure recovery, mass capture, a nd flowfield pressure distortion (the ratio of maximum static pressure to minimum static pressure generated at the inlet exit plane). Additi onally, an inviscid parametric study was performed by employing soluti ons to the Euler equations to optimize a cubic polynomial that defined the longitudinal sidewall geometry. A final viscous flowfield solutio n of the optimized inviscid inlet geometry yielded inlet performance i mprovements; however, inlet top-wall surface boundary-layer shock wave separation interactions persisted. Hence, this numerical study demons trated that enhanced performance is obtainable via curved-wall geometr ic modifications to the standard planar-sidewall inlet design, althoug h future work should employ constraints to mitigate detrimental flow s eparation effects.