Hypersonic Boundary Layer Transition to Turbulence on a Spherical Forebody

We investigate the influence of distributed surface roughness on boundary layer transition and heat transfer augmentation in hypersonic flow over a hemisphere. We consider the experimental dataset of Hollis 2017 at Mach 6 and perform high-fidelity numerical simulations to understand the physical mechanisms driving roughness-induced transition. Our analysis focuses on a roughness configuration that corresponds to ��⁄�� ≈ 0.5 and ���� ≈ 0.6 (�� is roughness height and �� is the effective slope). Distinctive heat flux streak patterns observed in the experiments during transition are reproduced in the simulations.