摘要
凹腔广泛存在于航空航天飞行器表面,如部件安装缝隙、高温烧蚀剥离等,对边界层转捩过程具有重要影响,是飞行器气动设计需要重点考虑的因素之一。为了探究不同尺度凹腔对边界层扰动波的影响规律,本文在固定来流条件下针对不同尺度的壁面凹腔,采用线性稳定性分析和高精度直接数值模拟,研究了高超声速(Ma=5.92)和超声速(Ma=1.38)边界层内扰动波经过凹腔的演化过程。结果表明:凹腔内部存在较强的回流区,其涡结构随着凹腔尺寸的增大变得复杂。对于高超声速流动,当凹腔位于快慢模态同步点上游时会促进扰动波发展,而位于同步点附近或下游时则起到抑制作用,且当凹腔位于同步点位置时抑制效果最佳;增加凹腔尺度(宽度或深度)会强化其对扰动波的控制效果。对于超声速流动,在不稳定区间范围内凹腔总是促进扰动波增长,并且随着凹腔尺度的增加促进效果增强。当凹腔尺度超过临界值后,凹腔内流动会发生自激振荡,进而给下游边界层引入新的扰动源,促进转捩的发生。本文研究结果对飞行器表面气动设计与热防护提供了重要参考。
Cavities such as installation gaps and high-temperature ablation stripping widely exist on the surfaces of aerospace vehicles.Their effects on the boundary-layer transition process are vital and thus need to be considered in the aircraft aerodynamic design.In order to explore the influence of cavities on the boundary-layer transition,this paper studies the evolutions of disturbance waves in both hypersonic(Ma=5.92)and supersonic(Ma=1.38)boundary layers passing through cavities of different sizes by using linear stability analysis and high-precision direct numerical simulations.The results show a strong recirculation zone inside the cavity,in which vortical structures become more complex with the increase of the cavity size.For hypersonic flows,when the cavity is located upstream of the synchronization points of the fast and slow modes,it promotes the development of disturbance waves.However,the opposite is true when the cavity is located near or downstream of the synchronization points.The suppression effect is the most significant for the cavity located at the synchronization point.Increasing the cavity size(width or depth)will strengthen its control effect on disturbance waves.For supersonic flows,the cavity always promotes disturbance growth in unstable regions,and the promotion effect increases with the increase of the cavity size.When the cavity size exceeds the critical value,the flow in the cavity can generate self-excited oscillations,which will introduce new disturbance sources to the downstream boundary layers and promote the transition.The results of this study are essential for aerodynamic design and thermal protection of aircraft surfaces.
作者
冯烁
王伯福
涂国华
武健辉
陈坚强
杨强
FENG Shuo;WANG Bofu;TU Guohua;WU Jianhui;CHEN Jianqiang;YANG Qiang(Shanghai Institute of Applied Mathematics and Mechanics,School of Mechanics and Engineering Science,Shanghai University,Shanghai 200072,China;National Key Laboratory of Aerospace Flight Aerodynamics Science and Technology,Mianyang 621000,China;China Academy of Launch Vehicle Technology,Beijing 100076,China)
出处
《空气动力学学报》
CSCD
北大核心
2023年第11期56-70,I0002,共16页
Acta Aerodynamica Sinica
基金
国家自然科学基金(92052301,12272395,11972220),空天飞行空气动力科学与技术全国重点实验室开放课题。
关键词
高超声速流动
凹腔
边界层转捩
扰动演化
hypersonic flow
cavity
boundary layer transition
disturbance evolution
