Study of supersonic flow field control mechanism with micro jet

An numerical investigation was conducted to study the influence of micro jet with different total injection pressure on the supersonic flow field (Ma=2.9) for a 24° compression corner. The ejecting direction is vertical to incoming flow. The results show that the velocity of the fluid downstream the micro jet decreases due to the obstruction of micro jet, and then the decrease can weaken the separation shock intensity. In addition, high-energy fluid is brought into the bottom of the boundary layer near the wall to activate it to be fuller with the downwash effect of counter-rotating vortex pair generated by coupling of micro jet and mainstream, which leads to the stronger ability of resisting adverse pressure and the separation of the boundary layer. The activation ability enhances with the increase of total injection pressure. Weighing the control result and injection power, we think the scheme is the best when the total injection pressure ratio (total injection pressure/total freestream pressure) is 0.60. The boundary layer separation area is restrained by nearly 70%, the distance of the intersection point of λ shock wave and the wall is reduced by almost 37%, and the separation shock intensity is weakened by nearly 12% under this scheme.