Global linear analysis of Stetson's Mach 8 blunt cone experiment*

Experiments by Stetson et al. 1984 recorded in detail the disturbances present in the laminar boundary layer on a blunt cone at Mach 8 with two nose-radii. The authors observed, for large nose bluntness, large fluctuation amplitude in the entropy layer, above the boundary layer, near the blunt nose which moved down into the boundary layer as they traveled downstream. Understanding the development of the entropy layer instability will be important for transition prediction on similar geometries with various nose radii. In this work we study the perturbation behavior and receptivity through global linear analysis of the blunt cone flow. We compute and analyze direct and adjoint modes which reveal the spatially unstable modes within the boundary layer and their receptivity to free-stream disturbances, which travel through the bow shock, while comparing their structure to that seen in the experiments by Stetson et al.