航空学报 > 2017, Vol. 38 Issue (11): 121345-121345   doi: 10.7527/S1000-6893.2017.121345

飞行器双自由度耦合振荡的数值模拟方法

肖中云, 刘刚, 江雄, 王建涛   

  1. 中国空气动力研究与发展中心 计算空气动力研究所, 绵阳 621000
  • 收稿日期:2017-04-21 修回日期:2017-06-16 出版日期:2017-11-15 发布日期:2017-06-16
  • 通讯作者: 肖中云 E-mail:scxiaozy@sina.cn
  • 基金资助:

    国家"973"计划(613221);国家自然科学基金(11572341);国家重点研发计划(2016YFB0200704)

Numerical simulation methods for 2DOF coupled oscillations of aircraft

XIAO Zhongyun, LIU Gang, JIANG Xiong, WANG Jiantao   

  1. Computational Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China
  • Received:2017-04-21 Revised:2017-06-16 Online:2017-11-15 Published:2017-06-16
  • Supported by:

    National Basic Research Program of China (613221);National Natural Science Foundation of China (11572341); National Key Research and Development Program (2016YFB0200704)

摘要:

针对模拟双自由度(2DOF)运动的"PQR"强迫振荡试验装置,通过坐标变换,将机构运动转化为空间欧拉角进行表示,实现对机构俯仰/偏航、俯仰/滚转和偏航/滚转等3种耦合运动的统一描述,采用预定运动轨迹的动网格计算技术,构造了基于非定常雷诺平均Navier-Stokes (URANS)方程的飞行器双自由度振荡数值模拟方法。围绕某复杂构型飞行器低速流动,在模型迎角10°、滚转角±40°、偏航角±40°振荡预设条件下分别对单自由度偏航、滚转振荡和双自由度偏航/滚转振荡进行了模拟,得到的气动系数迟滞回线在形态和量值上与风洞试验结果吻合,证明当前方法可以作为飞行器复杂耦合运动的一种有效研究手段。针对偏航/滚转耦合振荡,从运动形式和气动特性上与单独偏航、滚转运动进行了对比分析,结果表明,耦合运动在气流角、绕体轴的旋转角速度等方面与单自由度叠加效果不同,力矩系数迟滞回线存在曲线交叉的现象,表现出与单自由度振荡不同的阻尼特性。在当前模拟状态下,偏航/滚转振荡流场以横向分离涡运动为主要特征,可以推测大迎角情况下纵横向分离涡流动结构更加复杂,耦合作用更强,需要进一步在分离流模拟方法上开展研究。

关键词: 双自由度, 大幅振荡, 耦合运动, 非定常, 数值模拟

Abstract:

Focusing on the "PQR" forced oscillation test apparatus for modeling Two-Degree-of-Freedom (2DOF) motions, coordinate transformation is performed to obtain unified Euler angle descriptions of the pitch/yaw, pitch/roll and yaw/roll coupled motions. Based on moving grids for prescribed motion and Unsteady Reynolds Averaged Navier-Stokes (URANS) equations, a numerical algorithm is developed to simulate coupled oscillation of aircrafts. Surrounding low speed flows of a complex aircraft, single-degree oscillations of yaw and roll and yaw/roll coupled oscillation are respectively computed at angle of attack of 10° and amplitude of oscillation of 40°. The numerical results agree well with the experimental data, showing that current algorithm has promising potentials in simulation of complicated coupled motions of aircrafts. As for moving process and aerodynamics, the yaw/roll coupled motion is compared with the super position of single yaw and roll oscillations, which shows that differences exist in body angular velocities and flow angles,and the moment hysteresis curve of the yaw/roll coupled motion shows crossings, indicating totally different damping characteristics from single DOF oscillation. In current yaw and roll oscillations, flows are characterized by laterally separated vortexes. It is assumed that at high angle of attack, when flows are more complicated with lateral and longitudinal vortexes and strong coupled effects, more studies should be done on numerical methods of highly separated flows.

Key words: 2DOF, large amplitude oscillation, coupled motion, unsteady, numerical simulation

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