Implicit large-eddy simulation of an over-expanded screeching rectangular jet  

作　　者：Bao CHEN Xiaoqing QIANG Fei WU Mingsui YANG Weipeng LI 

机构地区：[1]School of Aeronautics and Astronautics,Shanghai Jiao Tong University,Shanghai 200240,China [2]AECC Shenyang Engine Design and Research Institute,Shenyang 110015,China

出　　处：《Chinese Journal of Aeronautics》2024年第11期203-216,共14页中国航空学报（英文版）

基　　金：support of the National Natural Science Foundation of China(No.12372221)is acknowledged。

摘　　要：Implicit large-eddy simulation of an over-expanded screeching rectangular jet is performed with a seventh-order finite difference scheme.Good agreement is found between the predicted flow-and acoustic fields with the experimental observations.Fourier decomposition,phase-averaging analysis and Spectral Proper Orthogonal Decomposition(SPOD)are used to investigate the origin of the screech,the shock leakage during the shear-layer flapping,and the distinguishing fluctuating characteristics in the minor-and major-axis plane of the rectangular jet.It finds that the screech is radiated from the end of the forth shock cell,where the interaction of the shock waves with the shear layer causes periodic leakages of shock-wave tips in the minor-axis plane,resulting in the generation of intense acoustic waves in the surrounding air.An obvious flapping mode at the same frequency of the screech is captured in the minor-axis plane and dominates the dynamic motions of the rectangular jet.The SPOD modes of pressure and velocity fluctuations at the screech frequency help to reveal the relationship between the screech generation and the coherent structures.

关 键 词：Over-expanded rectangular jet Screech Spectral proper orthogonal decomposition Coherent structures Shock waves 

分 类 号：V271.4[航空宇航科学与技术—飞行器设计]