摘要
数值模拟研究了Re=4×10^(4)时小迎角下表面局部振动激励对SD8020翼型气动特性的影响,从时均化和非定常流动两个方面分析了频率和幅值两个振动激励参数对于翼型分离和转捩特性的作用。结果表明,迎角2°和3°时局部振动激励能够有效对流场施加影响,促进层流分离泡结构的转变,改善翼型的气动性能。同时研究发现,振动频率在不同迎角下对翼型气动特性和流场结构的影响规律类似,频率f=32 Hz时气动性能提升最明显;而随着振动幅值的增加,层流分离泡长度减小且整体向前缘移动。进一步非定常分析表明,迎角2°和3°时流场在同一振动激励参数下表现出相似的非定常涡演化过程,弦向位置的压力脉动频率与振动激励频率一致,此时流场的非定常流动特征由振动激励主导。
The effect of surface local vibration excitation on the aerodynamic characteristics of SD8020 airfoil under small angles of attack is studied by numerical simulation at Re=4×10^(4).The influence of vibration frequency and amplitude on the flow characteristics of airfoil is studied from time averaged and unsteady aspects.The results show that local vibration at 2°and 3°can effectively affect flow field,promote the transformation of the laminar separation bubble structure and improve the aerodynamic performance of the airfoil.It is found that the effects of vibration frequency on aerodynamic characteristics and flow field structure of airfoil are similar under different angles of attack.When f=32 Hz,the improvement of aerodynamic characteristic is the most effective.With the increase of the vibration amplitude,the separation bubble structure span becomes smaller and moves towards the leading edge.The further unsteady analysis shows that the evolution process of unsteady vortex presents the similar mode under the same control strategy.And pressure pulsation frequency at chordal position is consistent with the vibration excitation frequency.It can be found that the unsteady characteristics of the flow field are dominated by the vibration excitation under this research condition.
作者
金周
夏天宇
董昊
JIN Zhou;XIA Tianyu;DONG Hao(College of Aerospace Engineering,Nanjing University of Aeronautics&Astronautics,Nanjing 210016,China;State Key Laboratory of Mechanics and Control for Aerospace Structures,Nanjing University of Aeronautics&Astronautics,Nanjing 210016,China)
出处
《南京航空航天大学学报》
CAS
CSCD
北大核心
2023年第4期676-685,共10页
Journal of Nanjing University of Aeronautics & Astronautics
关键词
低雷诺数
层流分离泡
局部振动
流动控制
非定常流动
low Reynolds number
laminar separation bubble
local vibration
flow control
unsteady flow
