摘要
来流扰动感受性是边界层转捩的起始阶段,能决定边界层扰动以何种路径触发转捩.目前二维感受性研究较为充分,但现实来流扰动往往以非零角入射,导致空间扰动在圆锥周向上存在分量,造成感受性呈现三维特征,该问题研究偏少.前期仅研究了低频慢声波入射的三维感受性,对于不同类型扰动的三维感受性问题还未做系统性研究.本文采用高精度三维数值模拟技术和线性稳定性理论,开展有入射角的不同频率快/慢声波、熵波和涡波的钝锥三维感受性研究.结果发现,入射慢声波能够激发边界层第一和第二模态;快声波很难激发不稳定模态;熵波和涡波在低频条件下难以激发第一模态,但在高频下可激发第二模态.扰动入射角可造成感受性因周向位置而异,体现在主导扰动形式的差异和边界层扰动幅值的差异.不同扰动类型、频率下这种差异表现出不同的规律,入射正面、背面和侧面都有可能是最强感受性.导致这些现象可能是上游头部和入射正面扰动的共同作用结果.
Receptivity to freestream disturbances is the initial stage of the boundary-layer transition process,which can determine the final path of boundary-layer disturbance triggering transition.At present,there is relatively sufficient research on the receptivity of two-dimensional boundary layers to zero incident angle disturbances.In fact,the freestream disturbances often propagate into the boundary layer in the form of non-zero incident angle,resulting in a component of spatial disturbance in the circumferential direction of rotating body(such as a cone).It is a receptivity problem with distinct three-dimensional features.However,there is relatively little research on this three-dimensional receptivity issue.The preliminary work only studied the three-dimensional receptivity to low-frequency incident slow acoustic waves.There has not been a systematic study on the threedimensional receptivity to different types of freestream disturbances.The three-dimensional receptivity of a blunt cone to different freestream disturbances is studied in this work.Firstly,a high-resolution numerical simulation method is used to investigate the three-dimensional receptivity process by introducing freestream disturbances with an incident angle of 15°.The freestream disturbances include fast acoustic wave,slow acoustic wave,entropy wave,and vortex wave.Their frequencies are chosen as dimensionless 1.1 and 5,corresponding to the first mode frequency and the second mode frequency,respectively.Then,the phase velocity and shape function of the boundary-layer disturbances at each position of circumference for the numerical results are obtained by Fourier transform.To explain the receptivity mechanisms,the corresponding results by linear stability analysis are obtained for comparisons.The results are shown below.The first mode and the second mode of the boundary layer can be effectively excited by the incident slow acoustic waves;it is difficult for the incident fast acoustic waves to excite unstable modes in the boundary layer;the incident
作者
万兵兵
胡伟波
李晓虎
黄文锋
陈坚强
涂国华
Wan Bing-Bing;Hu Wei-Bo;Li Xiao-Hu;Huang Wen-Feng;Chen Jian-Qiang;Tu Guo-Hua(State Key Laboratory of Aerodynamics,Mianyang 621000,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第23期130-143,共14页
Acta Physica Sinica
关键词
感受性
来流扰动
数值模拟
稳定性分析
receptivity
freestream disturbances
numerical simulation
stability analysis
