Direct numerical simulation of 3-D hypersonic boundary layer receptivity to freestream disturbances

In direct numerical simulation (DNS) of the receptivity to freestream disturbances and the laminarturbulent transition process of hypersonic boundary layers, it is necessary to consider the effect of the interaction between the bow shocks and wave fields. In previous papers, we developed a fifth-order shockfitting numerical method and conducted the DNS of the generation of boundary layer instability waves due to freestream acoustic disturbances for a 2-D Mach 15 flow over a parabolic leading edge. It was shown that instability waves developed in hypersonic boundary layers behind bow shocks contain both the first and second mode waves. The use of the high-order.shock fitting scheme makes it possible to accurately simulate physical bow-shock oscillations and interactions. This paper extends the previous 2-D work to a 3-D shockfitting scheme for the DNS of 3-D hypersonic flows over blunt cones of arbitrary cross sections and over blunt wedges. The new 3-D shock-fitting scheme is then used to study the receptivity of both axisymmetric and 3-D hypersonic boundary layers to freestream disturbances in Mach 15 flows over a parabolic cone and a parabolic wedge. The receptivity characteristics of axisymmetric and planar hypersonic boundary layers over blunt bodies are compared.