小攻角下波纹壁对圆锥高超声速边界层稳定性的影响

Effect of Wavy Wall on the Stability of Conical Hypersonic Boundary Layer at Small Angle of Attack

为了获得高升阻比,高超声速飞行器飞行通常带有一定攻角。波纹壁是在0°攻角条件下可以延迟高超声速边界层转捩的潜在手段,但在带攻角条件下波纹壁是如何影响不稳定波发展的目前尚不明晰。为研究在小攻角条件下波纹壁对高超声速边界层内不稳定波发展的影响,在Mach数为6的Ludwieg管风洞中采用高速红外相机和高频压力传感器(PCB)对1°攻角光滑和波纹壁尖锥进行了边界层稳定性的实验研究,重点分析了不稳定波沿不同方位角和流向位置的发展。实验结果显示:1°攻角条件下主导高超声速边界层转捩的不稳定波是第2模态波。1°攻角条件下,波纹壁在45°方位角下对转捩没有延迟效果,而在90°、 135°和180°方位角下波纹壁对转捩具有促进效果。

In order to obtain a high lift-drag ratio,hypersonic vehicles usually fly with a certain angle of attack.As a potential means to delay hypersonic boundary layer transition at 0°angle of attack,it is not clear how wavy wall affect the deve-lopment of instability waves with angles of attack.In order to study the influence of wavy wall on the development of instability waves in hypersonic boundary layer at small angle of attack,the stability of boundary layer was studied by adopting high-speed infrared camera and high-frequency pressure sensor(PCB)in Mach 6 Ludwieg tube wind tunnel.The development of instability waves along different azimuths and flow directions was analyzed.The experimental results show that the instability waves leading transition at 1°angle of attack are the second-mode waves.Under the condition of 1°angle of attack,the wavy wall has no delay effect on transition at 45°azimuth angle,but has a promotion effect at 90°,135°and 180°azimuth angles.