High Reynolds and Mach number effects on transition behavior on a flared cone-swept fin configuration

Laminar-turbulent transition in hypersonic boundary layers significantly influences heat transfer, skin friction, and flow separation. To examine the combined effects of shock wave-boundary layer interaction (SBLI) and adverse pressure gradients on boundary layer transition under hypersonic conditions, a flared cone-swept fin configuration was designed. High-fidelity transition data were obtained through wind tunnel experiments utilizing temperature-sensitive paint (TSP), temperature sensors, and high-frequency pressure sensors from PCB Piezotronics (PCB). TSP measurements revealed a triangular high-heat-flux region at the rear of the model, induced by the interaction between SBLI and the adverse pressure gradient. Temperature sensors provided precise wall heat flux, capturing a distinct “growth-decrease-regrowth” heat flux distribution pattern along the flared cone, highlighting the complex interplay between flow structures and transition phenomena. PCB sensors identified dominant instability modes, including low-frequency disturbances and second-mode instabilities. Furthermore, numerical simulations validated the wind tunnel results by reproducing the basic flow structures. This study presents the comprehensive wind tunnel dataset on transition for a complex configuration influenced by both SBLI and adverse pressure gradients, assessing the effects of Reynolds and Mach numbers on the flared cone-swept fin configuration. The findings offer valuable insights for transition prediction and thermal protection design in hypersonic vehicles with complicate fin-body interactions.