Laminar-turbulent transition on a flared cone at mach 6

Direct Numerical Simulations (DNS) are carried out to investigate the laminar-turbulent transition for a flared cone at Mach 6. The cone geometry of the flared cone experiments in the Boeing/AFOSR Mach 6 Quiet Tunnel (BAM6. QT) at Purdue University is used for the simulations. In the linear regime, an increasing stagnation pressure leads to higher N-factors and an increase of the most unstable frequency band. Low grid-resolution simulations are carried out to identify the azimuthal wave number for a specific set of conditions that led to the strongest secondary growth rate in a fundamental resonance scenario. Sub-sequently, for the case which led to the strongest resonance onset, detailed investigations were carried out using high-resolution DNS. The simulations results exhibit streamwise streaks of high skin friction and of high heat transfer at the cone surface. Streamwise streaks on the flared cone surface were also observed in the experiments carried out at the BAM6. QT facility using temperature sensitive paint.