高超声速边界层中自由来流强迫激发的非模态扰动的激励：第三部分——壁面温度与头部钝度的影响
Excitation of non-modal perturbations in hypersonic boundary layers by free stream forcing. Part III: effects of wall temperature and nose bluntness
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中文总结 AI 辅助
本文通过七案例研究，基于SF-HLNS和渐近分析，揭示头部钝度（R）增强驻点涡量扰动，壁温降低（T_w）增强涡量但削弱升力效应，净效果为下游扰动增强，并建立标度律，完善非模态感受性理论，助力转捩预测。
中文摘要 AI 辅助
本文是关于高超声速钝头边界层中非模态扰动激励研究系列的第三部分。基于第一部分（Zhao & Dong, J. Fluid Mech. 2025, vol. 1013: A44）提出的数值激波拟合谐波线性化Navier-Stokes（SF-HLNS）方法以及第二部分（Dong et al., J. Fluid Mech., 审稿中）发展的渐近分析，本工作通过七个详细案例研究，专门聚焦于头部钝度（雷诺数R）和壁面温度T_w对感受性效率的影响。通过三步渐近模型分析，下游扰动幅度由两个不同因素控制：通过激波-扰动相互作用和减速对流机制确定的驻点涡量扰动，以及由升力机制驱动的非模态扰动的抛物线演化。增加R强烈放大驻点涡量响应，而对升力效应仅有轻微增强。相反，降低T_w增强了驻点涡量扰动，但略微削弱了升力效应；净结果是随着T_w降低，下游扰动幅度总体增强。此外，建立了感受性效率关于R和T_w的显式标度律。本研究完善了高超声速钝头边界层中非模态感受性的理论基础，并朝着基于物理的转捩预测框架迈出了关键一步。
英文摘要
This paper constitutes Part III of a series investigating the excitation of non-modal perturbations in hypersonic blunt-nose boundary layers. Based on the numerical shock-fitting harmonic linearised Navier-Stokes (SF-HLNS) approach presented in Part I (Zhao & Dong, J. Fluid Mech. 2025, vol. 1013: A44) and the asymptotic analysis developed in Part II (Dong et al., J. Fluid Mech., under review), the present work focuses specifically on the influence of nose bluntness (Reynolds number R) and wall temperature T_w on receptivity efficiency through seven detailed case studies. Analysed via the three-step asymptotic model, the downstream perturbation amplitude is governed by two distinct factors: the stagnation vorticity perturbation, determined through shock-perturbation interaction and the slow-down convection mechanism, and the parabolic evolution of non-modal perturbations driven by the lift-up mechanism. Increasing R strongly amplifies the stagnation vorticity response, with only mild enhancement of the lift-up effect. In contrast, decreasing T_w strengthens the stagnation vorticity perturbation, but slightly weakens the lift-up effect; the net result is an overall intensification of the downstream perturbation amplitude with decreasing T_w. Furthermore, explicit scaling laws for receptivity efficiency with respect to R and T_w are established. This study completes the theoretical foundation for non-modal receptivity in hypersonic blunt boundary layers, and serves as a key step toward a physics-based transition prediction framework.
发表机构
- Tianjin University（天津大学）
- Institute of Mechanics, Chinese Academy of Sciences（中国科学院力学研究所）
机构由 AI 辅助整理，请以论文原文为准。
