Thomas ZIELINSKI, José CARDESA, Guillaume BEGOU, Jean-Philippe BRAZIER, Laurent MUSCAT, Marina OLAZABAL-LOUMÉ
DOI Number: N/A
Conference number: HiSST-2025-174
Boundary layer transition is of particular interest in the prediction of the aerodynamic performances and maneuverability of a given hypersonic vehicle. However, it has been found to be highly sensitive to flow parameters such as the Mach number, unit Reynolds number, cross-flow effects and wall temperature. Besides, from a numerical point of view, it is particularly difficult to obtain representative boundary-layer profiles to understand and then model these effects on the dominant instability modes. In this paper, a methodology relying on metric-based mesh adaptation has been validated and applied to address these issues. More specifically, the effects of the unit freestream Reynolds number, the wall temperature ratio Tw/Tr and the angle of attack on various boundary layer profiles and the typical instability waves (cross-flow instability, first and second Mack modes) for a sharp 7-degree cone geometry are investigated. It has been observed that the increase in unit Reynolds number destabilizes all modes. Moreover, it was shown that the ratio Tw/Tr has a drastic effect on these modes. Indeed, although the second Mack mode is strongly destabilized when lowering the Tw/Tr ratio, the highly oblique modes behaved in the opposite fashion, being strongly destabilized with an increase of Tw/Tr. Below Tw/Tr ≈ 0.3, the first mode became completely stable and the crossflow mode was always unstable for all the chosen Tw/Tr values. Finally, it has been found that the angle of attack significantly destabilized the crossflow instability by increasing the values of |wmax/Ue| and the variation of edge quantities across the flowfield due to a stronger azimuthal pressure gradient induced by the curved bow shock.