摘要
采用直接数值模拟方法计算了8个不同球头半径的钝锥基本流,运用线性稳定性理论分析了钝度对边界层稳定性的影响。结果表明,随钝度增大,边界层内的不稳定区向下游移动,第二模态的最大增长率减小。在线性稳定性分析的基础上,研究了非线性扰动演化以及平均流修正对稳定性的影响。结果表明,在基本流中引入有限幅值扰动后,下游的平均流剖面会发生明显改变。流场稳定性发生显著变化,线性阶段最不稳定的第二模态波变得稳定,而第一模态波明显增长起来。第一模态波的快速增长使N值可以达到4,这将会对转捩有很大的促进作用。
Instabilities of boundary layers over blunt cones with eight nose radiuses are numerically studied.The effect of bluntness on the boundary layer stability is analyzed by linear stability theory.It is found that the passivation of the cone nose leads to a downstream movement of the unstable region and a decrease of the maximum growth rate of the second mode.On this basis,nonlinear disturbance evolution and the effects of the mean flow distortion on the stability are studied.The results reveal that when the disturbance with finite-amplitude is introduced into the flow,the downstream mean flow profiles are obviously modified.As a result,the second-mode,which is the dominant instability in linear growth stage,is damped greatly while the first mode wave is amplified significantly.The rapid growth of the first mode can reach N=4,which will considerably promote the transition.
作者
秦丽华
韩宇峰
曹伟
QIN Lihua;HAN Yufeng;CAO Wei(Department of Mechanics,Tianjin University,300072 Tianjin,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2023年第2期264-274,共11页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金资助项目(No.116722051732011)
国家重点研究发展计划资助项目(No.2016YFA0401200)。
关键词
高超声速边界层
钝度
直接数值模拟
稳定性分析
转捩预测
非线性扰动演化
hypersonic boundary layer
bluntness
direct numerical simulation
stability analysis
transition prediction
nonlinear disturbance evolution
