Influence of transverse jet on shock wave/boundary layer interaction and flow field of air rudder

The multi-scale flow coupling effects induced by shock wave/boundary layer interaction (SWBLI) exacerbate thermal management challenges in hypersonic aircraft. This study focuses on the air rudder to investigate the influence mechanisms of the transverse jet on SWBLI and aerothermodynamic characteristics within the rudder gap region. The numerical method has been verified with the experimental data in public literature, and a grid independence analysis has been carried out. Research results indicate that as the total pressure ratio between the jet and the freestream increases, the coverage area of thermal protection on the rudder leading edge gradually improves. However, the interaction between the jet separation shock and the rudder leading-edge shock results in a sharp rise in the peak heat flux. For a jet Mach number of 1 and a specific heat ratio of 1.4, the jet flow field characteristics remain consistent at identical mass flow rates with fixed freestream conditions and constant total jet temperature. A reduction in orifice radius balances an increase in jet pressure ratio, governing the radial expansion scale of the jet. With rudder deflection, the transverse jet effectively mitigates SWBLI by attenuating windward-side downwash effects. At 15° deflection, the jet reduces peak heat flux at the rudder shaft by 73.1% and decreases the gap region peak by 1200 kW/m2. Subsequent research should focus on the collaborative optimization of jet parameters and rudder geometry to avoid shock interference.