摘要
有迎角圆锥表面存在周向压力梯度,压力梯度驱使流体从迎风面的高压区向背风面的低压区流动,导致背风中心线附近出现大尺度流向涡结构,从而进一步失稳触发转捩。本文利用全局稳定性理论与e^(N)方法,研究3个不同工况下高超声速有迎角圆锥的流向涡转捩问题。研究发现,Mack模态在上游流向涡较弱时为主导模态,但当流场出现周向卷曲、流向涡逐渐增强时逐渐减弱,此时流向涡失稳模态出现,并逐渐成为主导不稳定性。基于全局稳定性得到不稳定模态的N值。结合风洞实验测量结果可判断,在迎角2°时转捩N值不到3,而在迎角4°、转捩完成时的N值可达6左右。
An inclined cone with exists on a azimuthal pressure gradient on its surface,which drives the flow from the high-pressure region on the windward side to the low-pressure region on the leeward side.This results in the formation of large-scale flow vortex structures near the leeward centerline,which further destabilizing and triggering transitions.Linear global stability analyses were conducted by solving the two-dimensional eigenvalue problem(BiGlobal)and using plane-marching parabolized stability equations(PSE3D)to reveal the instabilities of streamwise vortices on the leeward side of the cones.Results showed that the Mack mode instability prevails in the upstream region for all cases.As the leeward base flow begins to distort significantly,the Mack mode weakens,while the intrinsic instability modes emerge and eventually take over.The downstream development of N factors for the unstable modes is obtained by PSE3D.According to the measured transition locations in experiments,the transition N factors are estimated to be less than 3 for the cases with a 2-deg angle of attack and approximately 6 for the case with a 4-deg angle of attack.The low N-factor at the transition location of the case with a 2-deg angle of attack implies that non-modal growth of disturbances may play a role in the transition process.
作者
陈曦
涂国华
万兵兵
袁先旭
陈坚强
陈久芬
CHEN Xi;TU Guohua;WAN Bingbing;YUAN Xianxu;CHEN Jianqiang;CHEN Jiufen(State Key Laboratory of Aerodynamics,Mianyang 621000,China;Hypervelocity Aerodynamics Institute of China Aerodynamics Research and Development Center,Mianyang 621000,China)
出处
《空气动力学学报》
CSCD
北大核心
2024年第1期33-44,I0001,共13页
Acta Aerodynamica Sinica
基金
国家自然科学基金(12002354,12002353,92052301)。
关键词
边界层转捩
流向涡
全局不稳定性分析
风洞实验
N值
boundary-layer transition
streamwise vortices
global stability analysis
wind-tunnel experiment
N factor
