Shock-wave/boundary-layer interaction is a prime research topic in the design of hypersonic vehicles. For the proper designing of hypersonic vehicles, especially, their thermal protection systems, it is necessary to understand the time-dependent behavior of the wall properties and the corresponding pressure and thermal loads. Hence investigation is carried out to understand the unsteady nature of shock-induced laminar boundary layer separation for a simple canonical configuration of a two-dimensional ramp. A density-based non-reactive Navier-Stokes solver named rhoCentralFoam in openFOAM is employed in the present investigation. The detailed physics of laminar boundary layer separation in hypersonic flow is investigated through timewise behavior of the streamline patterns and the surface properties, such as the pressure, heat flux, and friction coefficients. It is found that at the onset of fluid flow it is its inviscid characteristics that are predominant and there is occurrence of very small separation bubble. The separation bubble grows, as the involvement of viscous characteristics increases gradually, and ultimately it attains a steady state. Because of separated boundary layer the heat flux and skin friction coefficients are found to follow the diffused V and deformed W shapes, respectively. The peaks of pressure and thermal loads are found to exist in the vicinity of the reattachment region. These peaks are higher in the initial stage of the process and attain steady state eventually. The high pressure and thermal loads may cause structural damage to the vehicle and hence their correct prediction is necessary. Thus, the current investigation is helpful in the design of thermal protection systems of hypersonic vehicles.

中文翻译：

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高超声速流中层流分离气泡瞬态性质的数值研究

冲击波/边界层相互作用是高超音速飞行器设计中的主要研究课题。为了正确设计高超音速飞行器，尤其是它们的热保护系统，有必要了解壁面特性的时间相关行为以及相应的压力和热载荷。因此，进行了调查以了解二维斜坡的简单规范配置的冲击引起的层流边界层分离的不稳定性质。本研究采用基于密度的非反应 Navier-Stokes 求解器在 openFOAM 中命名为 rhoCentralFoam。通过流线模式的时间行为和表面特性（如压力、热通量、和摩擦系数。发现在流体流动开始时，其非粘性特性占主导地位，并出现非常小的分离气泡。随着粘性特性的介入逐渐增加，分离气泡逐渐增大，最终达到稳定状态。由于分离的边界层，热通量和皮肤摩擦系数被发现分别遵循扩散的 V 形和变形的 W 形。发现压力和热负荷的峰值存在于再附着区附近。这些峰值在过程的初始阶段较高，最终达到稳定状态。高压和热负荷可能会对车辆造成结构损坏，因此必须对其进行正确预测。因此，