Near-space hypersonic vehicles could encounter significant rarefied nonequilibrium effects during the flight through atmosphere, which largely influence the gas-surface momentum and heat transfer. In this paper, hypersonic boundary layer over a flat plate with velocity slip, temperature jump, and shear nonequilibrium effects is theoretically considered. The slip boundary conditions and nonlinear transport relations are embedded into the boundary-layer equations to describe the flow. Local similar solutions are derived, and key parameters for characterizing slip and shear nonequilibrium effects are determined. The velocity-slip and temperature-jump effects are determined by [(2−σu)/σu]Mae/Rex and [(2−σT)/σT]Mae/Rex respectively, and the shear nonequilibrium effect is characterized by Mae2/Rex. The obtained boundary-layer solutions are compared with the Navier–Stokes solutions for a Mach 4.5 slip flow, and the results of Direct Simulation Monte Carlo for a Mach 10 rarefied flow, good agreements are achieved. The separate and combined effects of velocity slip, temperature jump, and shear nonequilibrium on boundary-layer solutions and momentum/heat transfer are clarified. The results show that both the slip and shear nonequilibrium effects cause the boundary layer to become thinner and decrease the skin friction and Fourier heat conduction. However, with including sliding friction, the total heat flux might even increase as the slip degree increases. These results provide valuable insight into the boundary-layer characteristics of hypersonic near-continuum flows.

中文翻译：

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具有滑移和剪切非平衡效应的平板上的高超声速边界层

近空高超声速飞行器在穿越大气层时可能会遇到显着的稀薄非平衡效应，这在很大程度上影响气体表面动量和传热。本文从理论上考虑了平板上具有速度滑移、温度跳跃和剪切非平衡效应的高超声速边界层。将滑移边界条件和非线性输运关系嵌入到边界层方程中来描述流动。导出局部相似解，并确定表征滑移和剪切非平衡效应的关键参数。速度滑移和温度跳跃效应分别由 [(2−σu)/σu]Mae/Rex 和 [(2−σT)/σT]Mae/Rex 确定，剪切非平衡效应由 Mae2/Rex 表征。将获得的边界层解与马赫数 4.5 滑流的纳维-斯托克斯解以及马赫数稀薄流的直接模拟蒙特卡罗结果进行比较，取得了良好的一致性。阐明了速度滑移、温度跃变和剪切非平衡对边界层解和动量/传热的单独和组合影响。结果表明，滑移和剪切非平衡效应都会导致边界层变薄，并降低表面摩擦和傅立叶热传导。然而，如果包括滑动摩擦，总热通量甚至可能随着滑动程度的增加而增加。这些结果为了解高超声速近连续流的边界层特征提供了有价值的见解。