Interaction Between an Unstabilized Turbulent Boundary Layer and an Incident Oblique Shock Wave

不安定化된 亂流境界層 과 斜角入射衝擊波 와의 相互作용

An experimental investigation has been made to study the interaction between and incident oblique shock wave and an unstabilized turbulent boundary layer on a solid surface downstream of a porous surface with air injection through the porous surface. The boundary layer upstream of the interaction is unstabilized by the injection and provokes a shock wave which eventually interacts with the unstabilized boundary layer after reflecting from the upper wall of the test section. Three cases having diferent upstream Mach numbers and different shock strengthes are studied. According to the level of the unstabilization, two cases are of attached boundary layers and the other one is of a separated boundary layer. The result shows that the reflected wavey system is composed of the compression wave, expansion wave fan, and recompression wave like the ordinary interaction while the separated boundary layer strengthens the reflected expansion waves. The interactions of the attached boundary layers show a similar tendency of the upstream wall pressure distribution as that of the ordinary interacton but the pressure rise rather decays in the downstream region. In case of the separated boundary layer, the wall pressure continues to rise in the downstream as opposed ot the former cases. This indicates that the interaction region spreads out widely adn the viscous effect of the separated boundary layer smoothens the abrupt pressure increase due to the shock inpingement.

본 연구에서는 상호작용상류의 난류경계층에 분출을 가해서 경계층을 불안정 화시키고 이 불안정화된 난류경계층과 사각입사충격파와의 상호작용을 실험적으로 연 구하였다. Squire-Smith와는 다른 실험모형의 새로운 형태를 제시하였고 상호작용영 역에서 경계층의 압력분포 및 속도분포를 측정해서 충격파반사의 형태를 밝혔다.