Shock/shock interaction type transition control for drag and heat reduction by opposing jet in high-speed flow

The drag and heat flux induced by different types of shock/shock interactions (SSI) exhibit significant disparities. For high-speed vehicles, drag and heat reduction is of utmost importance in terms of energy conservation and flight safety. Therefore, this paper proposes a method of SSI type transition control using opposing jet to achieve drag and heat reduction. The nature of oblique/bow SSI undergoes a transition from type-IV to type-III under the control of opposing jet, as demonstrated by numerical simulations and wind tunnel experiments. The transition in SSI types serves as the primary mechanism of drag and heat reduction. A simplified theoretical model was established, suggesting that tht transition occurs because the impact of the opposing jet is equivalent to an increase in the cylinder radius. The impact can also be considered as analogous to the migration of the impinging shock in a parallel downward direction, resulting in a transition from the type-IV to the type-III SSI region. The effects of three parameters-pressure ratio-PR, temperature ratio-TR, and the impinging position-IR were studied. The peak wall pressure and heat flux exhibit a substantial reduction of 85.8 %, 79.3 % respectively under typical conditions.