Hypersonic Boundary Layer Transition - Application to High Speed Vehicle Design

This paper reports the boundary-layer transition characteristics of airbreathing hypersonic configurations and their impact on design environments. It discusses the evolution of the National Aerospace Plane configuration from an axisymmetric baseline to a wedgelike configuration where the transition mechanism is dominated by “natural” transition. Thenatural transition is characteristic of the “quiet” environment in freeflight of smooth slender vehicles. This type of transition mechanism gradually evolves spatially in different modes that can be computed analytically and verified experimentally. The paper discusses the effect of leading-edge bluntness, surface wall temperature, and adverse pressure gradient in compression ramp on transition. The effect of freestream Mach number, Reynolds number, and angle of attack are also studied over the range of peak aerodynamic heating conditions of the National Aerospace Plane environment. The transition behavior was investigated using e-type calculations based on a linear stability code known as the eMalik code.