Stationary Crossflow Transition Control Using Subcritical Vortices in Hypersonic Boundary Layers
Seminar
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Date
23 Sep 2026
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Organiser
Department of Aeronautical and Aviation Engineering
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Time
14:00 - 15:00
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Venue
TU107 Map
Summary
Abstract
Crossflow instability is a major pathway to transition over hypersonic swept surfaces, with important consequences for skin friction and aerodynamic heating. In this study, we examine the complete transition process under subcritical-mode control, from the modification of the dominant stationary vortex to secondary instability and final breakdown. We find that, at shorter wavelengths, stronger control continues to delay transition. At a moderately longer wavelength, however, excessive control eventually destabilises the control mode itself, causing premature breakdown and turning transition suppression into transition promotion.
Based on these results, we identify a saturation threshold for the control amplitude and wavelength. These results provide insight into the mechanisms and limitations of stationary-vortex control in hypersonic flows and offer practical guidance for roughness-based transition-control design.
Speaker
Prof. Caihong Su received her Bachelor's degree in Engineering Mechanics in 2003 and her PhD in Fluid Mechanics in 2008, both from Tianjin University. Upon completing her doctoral studies, she joined the faculty at Tianjin University and was promoted to Professor in 2018.
She currently leads the Laboratory of High-Speed Aerodynamics at Tianjin University. Her primary research interests lie in the prediction and control of transition in high-speed boundary layers. She is a member of the Fluid Mechanics Committee of the Chinese Society of Theoretical and Applied Mechanics and serves as the Deputy Head of the Turbulence and Stability Specialist Group.
