Crossflow Effects on the Global Stability of Hypersonic Compression Corner Flow

Hypersonic compression corner flow with crossflow at the leading edge of the flat plate is investigated through global stability analysis (GSA) and direct numerical simulation (DNS). Base flow conditions with a Mach number of 7.7 and a unit Reynolds number of [Formula: see text] are selected. The effects of varying sweep angles (0–50 deg) and ramp angles (12–15 deg) are examined. The results reveal multiple local maxima in temporal amplification rate with different spanwise wavenumbers signifying oscillatory modes in the presence of crossflow, one of which corresponds to the leading stationary mode observed in unswept flows. The introduction of crossflow induces streamwise periodicity in the reattached boundary layer. The critical ramp angle of 14 deg is further discussed, where the flow becomes globally stable at moderate sweep angles and globally unstable at higher sweep angles, with changes in the leading global mode under varying crossflow intensities. DNS of a globally unstable case demonstrates good agreement with the GSA’s most unstable mode during the linear growth stage. In the saturated stage, harmonics of the most unstable global mode are observed, followed by the emergence of broadband unsteadiness.