Shock/turbulent-boundary-layer interactions (STBLIs) are ubiquitous in high-speed flight and propulsion applications. Experimental and computational investigations of swept, three-dimensional (3-D) interactions, which exhibit quasi-conical mean-flow symmetry in the limit of infinite span, have demonstrated key differences in unsteadiness from their analogous, two-dimensional (2-D), spanwise-homogeneous counterparts. For swept interactions, represented by the swept–fin-on-plate and swept–compression–ramp-on-plate configurations, differences associated with the separated shear layers may be traced to the intermixing of 2-D (spanwise independent) and 3-D (spanwise dependent) scaling laws for the separated mean flow. This results in a broader spectrum of unsteadiness that includes relatively lower frequencies associated with the separated shear layers in 3-D interactions. However, lower frequency ranges associated with the global “breathing” of strongly separated 2-D interactions are significantly less prominent in these simple, swept 3-D interactions. A logical extension of 3-D interaction complexity is the compound interaction formed by the merging of two simple interactions. The first objective of this work is therefore to analyze the more complex picture of the dynamics of such interactions, by considering as an exemplar, wall-resolved simulations of the double-fin-on-plate configuration. We show that in the region of interaction merging, new flow scales, changes in separation topology, and the emergence of lower-frequency phenomena are observed, whereas the dynamics of the interaction near the fin leading edges are similar to those of the simple, swept interactions. The second objective is to evolve a unified understanding of the dynamics of STBLIs associated with complex configurations relevant to actual propulsion systems, which involve the coupling between multiple shock systems and multiple flow separation and attachment events. For this, we revisit the salient aspects of scaling phenomena in a manner that aids in assimilating the double-fin flow with simpler swept interactions. The emphasis is on the influence of the underlying structure of the separated flow on the dynamics. The distinct features of the compound interactions manifest in a centerline symmetry pattern that replaces the quasi-conical symmetry of simple interactions. The primary separation displays topological closure to reveal new length scales, associated unsteadiness bands, and secondary flow separation.

冲击/湍流边界层相互作用 (STBLI) 在高速飞行和推进应用中无处不在。扫描的三维 (3-D) 相互作用的实验和计算研究表明，在无限跨度的极限内表现出准圆锥平均流对称性，已经证明了不稳定与它们类似的二维 (2-D) 的关键差异)，展向齐次对应物。对于扫掠相互作用，由扫掠鳍板和扫掠压缩斜板构型表示，与分离的剪切层相关的差异可以追溯到 2-D（展向独立）和 3-分离平均流的 D（展向相关）标度法则。这会导致更广泛的不稳定性，其中包括与 3-D 相互作用中分离的剪切层相关的相对较低的频率。然而，在这些简单的扫描 3-D 相互作用中，与强烈分离的 2-D 相互作用的全局“呼吸”相关的较低频率范围明显不那么突出。3-D 交互复杂性的逻辑扩展是由两个简单交互合并形成的复合交互。因此，这项工作的第一个目标是通过将双翅片配置的壁解析模拟作为示例来分析这种相互作用的动力学的更复杂的图景。我们表明，在相互作用合并区域，观察到了新的流动尺度、分离拓扑的变化以及低频现象的出现，而鳍前缘附近相互作用的动力学类似于简单的扫掠相互作用。第二个目标是对与实际推进系统相关的复杂配置相关的 STBLI 动力学形成统一的理解，这些配置涉及多个激波系统和多个流分离和附着事件之间的耦合。为此，我们以一种有助于通过更简单的扫掠相互作用同化双翅流的方式重新审视缩放现象的显着方面。重点是分离流的基础结构对动力学的影响。复合相互作用的独特特征表现为中心线对称模式，取代了简单相互作用的准圆锥对称。