摘要
采用运动自由度不受约束的风洞自由飞试验技术,研究大钝头、小升阻比的类“联盟号”返回舱在跨声速区自由飞行时的运动特性与气动特性规律。以单平面光路拍摄返回舱模型在风洞中自由飞动态运动过程图像,经图像自动判读获取其运动轨迹与姿态角,并以参数微分法对模型运动姿态角进行线性与非线性气动参数辨识,得到模型俯仰方向的静、动稳定导数系数。研究结果表明:采用线性与非线性气动参数辨识所获得的静稳定导数系数Cmα均小于零,在数值上差距不大;从非线性气动参数辨识结果看,返回舱静稳定导数系数的数值主要由线性项Cmα0决定,非线性项Cmα^2α^2所占比例较小;类“联盟号”返回舱静稳定导数系数的非线性较弱,可近似用线性气动模型进行辨识。在试验迎角范围内,返回舱的动稳定导数系数呈现出非线性性质,且在小迎角范围内由线性项(Cmq+Cmα·)0决定,在大迎角范围内主要由非线性项(Cmq+Cmα·)2α^2主导。
This paper studies the motion and aerodynamic characteristics of the re-entry capsule with stable fins at transonic speed by the wind-tunnel free-flight test in which the motion freedom is not limited. When the wind tunnel test model flights freely by the observational window,the high speed camera captures the motion image immediately by a single light path, and then the model motion trajectory and attitude angle can be acquired by image acquisition software. Finally,the pitching static and dynamic derivatives coefficient are derived by the parameter differential method from the recorded angular motion of the model of more than two cycles with the linear and nonlinear motion equations. The result shows that the static derivative coefficient C mα obtained by the linear and nonlinear aerodynamic parameter identification is less than zero and the variation is not significant. From the results of nonlinear aerodynamic parameters identification, the value of static derivatives coefficient of the re-entry capsule is mainly determined by the linear term C mα 0 , and the nonlinear term C mα^ 2 α^ 2 is relatively smaller. The nonlinearity of the static derivatives coefficient is weak, which can be approximated by the linear aerodynamic model. The dynamic derivative coefficient of the re-entry capsule is nonlinear in the range of experimental angles of attack. It is determined by the linear term (C mq +C mα·) 0 in the range of small angle of attack, and dominated by the nonlinear term (C mq +C mα·) 2α^ 2 in large angle of attack.
作者
宋威
艾邦成
蒋增辉
鲁伟
Song Wei;Ai Bangcheng;Jiang Zenghui;Lu Wei(China Academy of Aerospace Aerodynamics,Beijing100074,China)
出处
《实验流体力学》
EI
CAS
CSCD
北大核心
2019年第4期89-94,共6页
Journal of Experiments in Fluid Mechanics
关键词
风洞自由飞试验
单平面光路
参数微分法
气动参数辨识
静动稳定导数系数
wind-tunnel free-flight test
single light path
parameter differential method
aerodynamic parameter identification
static and dynamic derivative coefficient
