Effect of Distributed Roughness Elements on Crossflow Transition in a Yawed Cone in a Mach 6 Wind Tunnel

Research on hypersonic crossflow transition holds significant engineering and scientific importance. This paper investigates the impact of distributed roughness elements (DREs) on crossflow transition for a cone set at a 6° angle of attack, using experimental methods. The research was conducted in the Mach 6 wind tunnel, employing temperature-sensitive paint (TSP) as the measurement technology. Two types of nosetip were examined: a sharp nosetip with a radius of 0.1 mm and a blunt nosetip with a radius of 2.5 mm. The circumferential wavenumbers of the DREs on the nosetip included k = 35, k = 50, and k = 70. The results indicate that the nosetip with DREs at k = 50 has a more pronounced effect in promoting boundary layer transition to turbulence on the leeward side of the cone compared to the nosetips with DREs at k = 35 and k = 70. However, all three types of DREs exhibit similar effects on transition on the windward side. Additionally, the bluntness of the nosetip, at R = 2.5 mm, diminishes the effectiveness of DREs in promoting transition; however, the degree of diminished effectiveness varies with the circumferential azimuth.