Flow characteristics around airfoils near transonic buffet onset conditions  

作　　者：Yanxiong ZHAO Zhixiong DAI Yun TIAN Yuexi XIONG 

机构地区：[1]School of Aeronautic Science and Engineering,Beihang University,Beijing 100083,China [2]China Helicopter Research and Development Institute,Jingdezhen 333001,China [3]National Lab for Aeronautics and Astronautics,Beihang University,Beijing 100083,China

出　　处：《Chinese Journal of Aeronautics》2020年第5期1405-1420,共16页中国航空学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 11802009)

摘　　要：In transonic flow,buffet is a phenomenon of flow instability caused by shock wave/boundary layer interaction and flow separation.The phenomenon is common in transonic flow,and it has serious impact on the structural strength and fatigue life of aircraft.In this paper,three typical airfoils:the supercritical OAT15A,the high-speed symmetrical NACA64A010,and the thin,transonic/supersonic NACA64A204 are selected as the research objects.The flow fields of these airfoils under pre-buffet and buffet onset conditions are simulated by Unsteady Reynolds Averaged Navier-Stokes (URANS) method,and the mode analysis of numerical results is carried out by Dynamic Mode Decomposition (DMD).Qualitative and quantitative analysis of the shock wave motion,shock wave intensity,shock foot bubble and trailing edge separation,and pressure coefficient fluctuation were performed to attain deep insight of transonic buffet flow features of different airfoils near buffet onset conditions.The results of DMD analysis show that the energy proportion of the steady mode of these airfoils decreases dramatically when approaching the buffet onset angle of attack,while the growth rate of the primary mode increases inversely.It was found that at the onset of buffet,there exist different degrees of merging behavior between shock foot bubble and trailing edge separation during one buffet cycle,and the instability of shock wave and separation induced shear layer are closely related to the merging behavior.

关 键 词：Dynamic Mode Decomposition Separated bubbles Shock waves Transonic buffet Transonic flow 

分 类 号：V211.41[航空宇航科学与技术—航空宇航推进理论与工程]