Lin HAN, Caihong SU
DOI Number: N/A
Conference number: HiSST-2025-204
This study investigates the effects of leading-edge shape on hypersonic crossflow receptivity to slow acoustic waves in a Mach 6 flow over swept flat plates. Three leading-edge geometries are examined: a cylindrical nose (with sharp curvature discontinuity) and two ellipsoidal noses (with smoother curvature transitions), designed to examine how geometric features—bluntness and nose-body junction abruptness—influence the excitation and evolution of crossflow traveling modes. Direct numerical simulations (DNS), combined with linear stability theory (LST) and parabolized stability equations (PSE), are used to resolve the receptivity process and downstream disturbance development for a target traveling mode. The steady base flow analysis shows that increased nose bluntness leads to a larger favorable pressure gradient, which consequently results in greater amplification of the crossflow instability mode as predicted by LST. DNS reveals that the traveling mode is excited primarily within the rapidly varying mean flow region near the leading edge. Importantly, the abrupt curvature discontinuity of the cylindrical nose induces localized scattering effects on disturbances, while ellipsoidal noses mitigate this scattering due to their gradual curvature transitions. Receptivity coefficients indicate that the cylindrical nose exhibits smaller values compared to the ellipsoidal cases. However, this reduced initial amplitude of the traveling mode through receptivity is offset by enhanced downstream instability amplification. Specifically, the stronger pressure gradient associated with the cylindrical nose promotes faster disturbance growth, ultimately leading to larger disturbance amplitudes downstream.