Generation of acoustic waves in the hypersonic boundary layer over a wavy wall

作     者：WenKai Zhu DingWei Gu YiDing Zhu CunBiao Lee WenKai Zhu;DingWei Gu;YiDing Zhu;CunBiao Lee

作者机构：State KeyLaboratory of Turbulence and Complex SystemsCollaborative Innovation Center of Advanced Aero-EnginePeking UniversityBeijing 100871China 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2022年第65卷第3期

页      面：62-70页

核心收录：

学科分类：082502[工学-航空宇航推进理论与工程] 08[工学] 0825[工学-航空宇航科学与技术] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.10921202,11221061,11632002,11521091,11602005 91752202) the National Key Project(Grant No.GJXM92579) 

主　　题：instability of boundary layers compressible flows hypersonic flows 

摘      要：The effects of a wavy wall on a hypersonic boundary layer of a flared cone are investigated using experimental measurements and direct numerical simulations(DNSs). Non-contact optical measurements using a focused laser differential interferometer(FLDI) show that a wavy wall can significantly suppress the second mode, and multiple perturbations of new frequencies are generated over the wavy surface, which agrees well with numerical results. Using Lagrangian tracking of marked particles, it is demonstrated that the wavy wall geometry can induce mean flow oscillations while exciting acoustic waves. The frequencies of the excited disturbances over a wavy wall agree with the classical Rossiter model. The superposition of a disturbance propagating downstream and an acoustic wave propagating upstream at the same frequency but with different amplitudes and propagation velocities results in a spatial distribution with a streamwise-oscillatory pattern over the wavy surface. A simple two-wave superposition model that takes into account the phase velocities and wavenumbers of the convective disturbance and acoustic wave can well describe the modal behavior of excited disturbances over a wavy wall.