Research on flow field structure and thermal environment effect of air rudder gap

High-speed air rudder faces a severe aerodynamic heating environment, particularly due to intense shock wave/boundary layer interactions (SWBLI) around the rudder gap. This paper numerically investigates the impacts of the incoming flow conditions and the rudder's structural parameters on gap flow structure and thermal environment. The numerical method has been validated against experimental data in the open literature, and the grid independency analysis has been performed. The results indicate that as the flight Mach number increases, aerodynamic heating around the rudder leading edge and gap intensifies. Under constant dynamic pressure design, weakened SWBLI around the gap lead to reduced overall heat flux inside the gap. As the rudder deflection angle increases, the SWBLI around the gap enhances, leading to an increase in peak heat flux within the gap. Additionally, an increase in the rudder bottom's passivation radius results in a decrease in heat flux at the rudder tip's stagnation point, but the SWBLI below the rudder tip intensifies.