分离流动诱发的失速颤振和锁频现象研究  

Separation flow induced stall flutter and frequency locking phenomena

作　　者：李国俊[1] 白俊强[1] 唐长红 李宇飞[1] 刘南 LI Guojun;BAI Junqiang;TANG Changhong;LI Yufei;LIU Nan(School of Aeronautics,Northwestern Polytechnic University,Xi’an 710072,China;AVIC Aerodynamic Research Institute,Shenyang 110034,China)

机构地区：[1]西北工业大学航空学院,西安710072 [2]中航工业空气动力研究院,沈阳110034

出　　处：《振动与冲击》2018年第19期97-103,111,共8页Journal of Vibration and Shock

基　　金：国家"973"计划(2014CB744804)

摘　　要：采用非定常雷诺平均N-S方程(Unsteady Reynold Averaged Navier-Stockes,URANS)模拟失速颤振中的非定常气动力,通过耦合结构运动方程,建立时域气动弹性分析方法,其中结构运动方程采用基于预估-校正技术的四阶隐式Adams线性多步法进行时域推进求解。首先对动态失速气动力响应和锁频区域的预测精度进行验证,确保求解器适用于模拟失速颤振。其次,采用该气动弹性分析方法对NACA23012翼型的颤振边界进行数值模拟,结果表明,预测得到的颤振速度边界和实验结果吻合较好。通过对失速颤振中的结构运动响应和流动特性进行分析,发现在失速颤振中前缘漩涡的产生和尾涡脱落是一种能量转换和注入机制,用以维持翼型的等幅振荡;同时失速颤振中出现的锁频现象是导致翼型在初始攻角为15°、16°和17°时颤振频率突然降低的主要原因。The unsteady Reynold averaged Navier-Stockes(URANS)equation was adopted to simulate unsteady aerodynamic force in stall flutter.Coupled with a structure’s dynamic equation,the time domain aero-elastic analysis method was established.The structure’s dynamic equation was solved in time domain using the fourth order implicit Adams linear multi-step method based on the prediction-correction technique.Firstly,the aerodynamic response of dynamic stall and the prediction accuracy of frequency locking region were verified to ensure the CFD solver being suitable to stall flutter simulation.Then,this aero-elastic analysis method was used to simulate the flutter boundary of NACA23012 airfoil.The results showed that the flutter velocity boundary predicted with the proposed method agrees well with the test results.Through analyzing structural motion responses and flow characteristics in stall flutter,it was found that the generation of leading edge vortices and wake shedding in stall flutter is an energy conversion and an injection mechanism to keep the constant amplitude oscillation of the airfoil;meanwhile,the frequency locking phenomenon occurring in stall flutter is the main reason to cause flutter frequencies abruptly dropping when the initial attack angle are 15°,16°and 17°,respectively.

关 键 词：失速颤振 锁频 动态失速 漩涡 能量 

分 类 号：V211.47[航空宇航科学与技术—航空宇航推进理论与工程]