Abstract The nose-tip bluntness effects on the hypersonic crossflow instability were experimentally investigated over a 7 ∘ half-angle straight cone at 6 ∘ angle of attack. The experiments were conducted in a Mach 6 wind tunnel at Reynolds number of 7 . 94 × 1 0 6 m − 1 using temperature-sensitive paint (TSP) and fast-response pressure transducers. The wavelet transform was applied to obtain the most amplified wavenumber of the stationary crossflow vortices. The stationary crossflow vortices with wavenumber of 40–60 and the traveling crossflow waves with characteristic frequencies of 9–20 kHz have been detected. TSP results indicate that the bluntness has little influence on the boundary layer transition location with a small nose-tip radius (smaller than 1.5 mm), while the transition front moves backward obviously with a larger nose-tip radius (larger than 2.5 mm). The developments of two types of crossflow instability, the stationary mode and the traveling mode, are both not sensitive to the bluntness when the nose-tip radius is below 1.5 mm. And the growth and saturation of the two types crossflow mode are both inhibited under larger bluntness. Besides, possible explanations for how the bluntness affects the transition location and crossflow instability is discussed.

中文翻译：

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鼻尖钝度对锥体高超声速横流不稳定性影响的实验研究

摘要 在 6 ∘ 攻角的 7 ∘ 半角直锥体上实验研究了鼻尖钝度对高超声速横流不稳定性的影响。实验是在雷诺数为 7 的马赫数为 6 的风洞中进行的。94 × 1 0 6 m − 1 使用温度敏感涂料 (TSP) 和快速响应压力传感器。应用小波变换来获得静止横流涡流的最大放大波数。已检测到波数为 40-60 的固定横流涡流和特征频率为 9-20 kHz 的行横流波。TSP 结果表明，钝度对鼻尖半径较小（小于 1.5 mm）的边界层过渡位置影响不大，而过渡锋明显向后移动，鼻尖半径更大（大于2.5毫米）。当鼻尖半径小于1.5 mm时，两种横流不稳定性即静止模态和行进模态的发展均对钝度不敏感。两种横流模式的增长和饱和都在较大的钝度下受到抑制。此外，讨论了钝度如何影响过渡位置和横流不稳定性的可能解释。