非旋转钝锥高超声速自由飞非线性角运动轨迹重构与分析

采用多阶段曲线拟合技术，对双平面拍摄风洞自由飞试验获得的高超声速下非旋转钝锥角运动观测值作了拟合，获得了与试验观测值重合度较好的拟合曲线，进而实现了对试验模型非线性角运动轨迹的重构，获得了5次试验的复攻角和总攻角曲线，并进而对非旋转钝锥非线性角运动的特点和规律进行了分析。结果分析表明：模型复攻角曲线可能逆时针方向转动也可能顺时针方向转动，甚至可能改变转动方向；复攻角曲线多呈“椭”圆锥运动，且椭圆运动的长轴在大小和方向上均可能发生变化；总攻角幅值呈振荡变化，但多呈总体上减小的趋势；由于角运动的非线性特性，同样的试验模型在不同的预置攻角情况下其角运动特性也呈现出很大的不同。

Trajectory reconstruction and analysis of nonlinear angular motion of hypersonic free-flight non-spinning cones

Employing multi-stage curve fitting procedure, the observations of hypersonic non-spinning blunt cones wind-tunnel free-flight tests with biplanar optical system are analyzed by nonlinear fitting. Perfect coincidence is acquired between the fitting curves and observations, and then trajectory reconstruction of the nonlinear angular motion of the models is achieved. Complex angle of attack and resultant angle of attack curves are obtained for five tests, and then the characteristics of the nonlinear angular motion of the non-spinning blunt cones are analyzed. The rotating direction of complex angle of attack curves is uncertain, and both clockwise and anticlockwise are present, sometimes there is even a change in rotating direction. Most complex angle of attack curves present elliptical cone motion, and the magnitude and direction of the long axis of ellipse are probably variable. The magnitude of resultant angle of attack decreases in general, though it is oscillatory. Due to the nonlinear characteristics, different characteristics exist for the angular motion with identical model at different preset angles of attack.