The effect of nosetip bluntness on instability development within the hypersonic boundary layer on a 7° half-angle cone is experimentally studied using high-speed calibrated schlieren visualizations and PCB pressure measurements. Experiments are performed in the Air Force Research Lab (AFRL) Mach-6 Ludwieg Tube at unit Reynolds numbers ranging from 13.72 × 10~6 to 22.71 × 10~6 per meter. The visualizations capture second-mode instability waves within the boundary layer for nosetip radii up to 2.54 mm. Quantitative data on second-mode instability waves including disturbance frequencies and integrated amplification rates (N factors) are calculated from the visualizations and PCB pressure measurements, and compared to parabolized stability equation (PSE) computations. The visualized instability features change dramatically for nosetip radii larger than 2.54 mm where nonmodal growth is expected. Unsteady features that extend above the edge of the boundary layer are observed and the visualizations are used to track individual instances throughout their development process. PCB measurements reveal high-frequency (150-250 kHz) pressure disturbances associated with the features.
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