Experiments were performed within Rutgers University’s Mach 3.4 wind tunnel to visualize the unsteady flow over a wall-mounted hemisphere using high-speed schlieren imaging and stereoscopic particle image velocimetry (SPIV). The hemisphere ($R=38.1\mathrm{mm}$) was placed within the wind tunnel’s naturally developing turbulent boundary layer, resulting in a boundary-layer thickness-to-radius ratio of 0.43. The hemisphere flowfield demonstrates many features that are characteristic of a traditional shock/boundary-layer interaction, such as unsteady motion associated with the foot of the upstream separation shock and subsequent incipient separation. In addition, a strong reattachment shock emanates from the forward side of the hemisphere where flow reattachment occurs. Cross correlation of the high-speed schlieren data indicates that the upstream shock-dominated flow is not strongly correlated with the downstream wake flow. The upstream shock structure dominates; it wraps around the sides of the hemisphere, leading to a potentially far-reaching influence. The SPIV velocity fields reveal the presence of a highly unsteady wake structure with a separated shear layer and a downstream recompression shock. The observations are consistent with recent studies concluding that the wake flow comprises two recirculating lobes with symmetry along the spanwise centerline. Turbulence statistics of the hemisphere wake and separated shear layer were also analyzed.

在罗格斯大学的 3.4 马赫风洞内进行了实验，以使用高速纹影成像和立体粒子图像测速 (SPIV) 来可视化壁挂式半球上的不稳定流动。半球（$\mathrm{电阻}=38.1\mathrm{毫米}$) 放置在风洞自然发展的湍流边界层内，导致边界层厚度半径比为 0.43。半球流场展示了许多传统激波/边界层相互作用的特征，例如与上游分离激波和随后的初期分离相关的不稳定运动。此外，强烈的重附冲击从发生流动重附的半球前侧发出。高速纹影数据的互相关表明上游激波主导流与下游尾流没有强相关性。上游冲击结构占主导地位；它环绕着半球的两侧，可能产生深远的影响。SPIV 速度场显示存在高度不稳定的尾流结构，具有分离的剪切层和下游再压缩冲击。观察结果与最近的研究一致，即尾流包括两个沿展向中心线对称的再循环瓣。还分析了半球尾流和分离的剪切层的湍流统计。