压力不匹配混合层中激波与流场结构的实验研究

Experimental Investigation on Shock Waves and Flow Structures in Pressure Unmatched Mixing Layer

为了研究压力不匹配混合层的流动结构以及激波与湍流边界层的相互作用,采用基于纳米粒子的平面激光散射技术(NPLS)和伪彩色处理方法获得了流场中Kelvin-Helmholtz涡、激波、湍流边界层以及边界层分离泡等流动精细结构。研究结果表明:压力不匹配导致混合层的转捩位置提前,大尺度涡的结构更加破碎,混合层向压力低的一侧发展。激波的作用使得边界层在激波入射点之后增厚,湍流脉动的加剧导致了激波入射点发生前后的偏移。

Nanoparticle-based planar laser scattering （NPLS） technique and pseudo-color processing technology were employed to investigate flow structures and interaction of shock waves and turbulent boundary layer. The images clearly displayed fine flow structures such as Kelvin-Helmholtz vortices, shock waves, turbulent boundary layer and separation bubble. The results show that the transition position of mixing layer advances and large scale structures become crushed due to the unmatched pressure. Meanwhile, the development direction is downside, which has lower pressure. Because of the interaction of shock waves and turbulent boundary layer, the boundary layer becomes thicker behind incidence point. Besides, the intensification of turbulence fluctuations is responsible for movement of incidence point.