有翼飞行器高超声速动导数的风洞自由飞测量

对具有典型意义的有翼航天飞行器模型在力学所JF 8A脉冲型高超声速风洞中M =6.2 6,M =7.91和M =9.2 9条件下进行了模型自由飞实验。由记录的运动经最大似然法作参数辨识后得到了它们的俯仰阻尼导数。实验结果显示 ,在实验范围内模型具有动态稳定性 ,同一名义实验条件下的重复性实验呈一致的运动规律并具有接近的动导数测量结果。实验范围内马赫数的变化 (从 6.2 6到 7.91 )以及模型质心位置的轴向移动 (从 0 .5 0到 0 .60 )没有导致俯仰阻尼系数的明显变化 ,其量值在- 1 .5附近。而马赫数 9.2 9时阻尼值变小 ,其主要原因可能是由雷诺数的变化所引起。此外 ,考虑恢复力矩的非线性影响后 ,辨识结果有所改善

Hypersonic pitching damp measurements for a winged vehicle by model free flight

Model free flight experiments were carried out in impulse hypersonic wind tunnel at Institute of Mechanics, Chinese Academy of Sciences under the Mach number conditions of 6.26, 7.91 and 9.29 to obtain pitching damp for a typical space shuttle model. The model movements were recorded by synchronized high speed photography. The pitching damps of models were obtained by parameter identification using maximum likelihood method. The results show that within the scope of experimental condition the models are all dynamically stable. The repeated experiments at same nominal condition show that models moved with same pattern and have close value of pitching damp. The variation of Mach number (from 6.26 to 7.91 ) and axis variation of model's center of gravity (from 0.50 to 0.60) cause little change of pitching damp and the value is about -1.5. The damp at Mach number 9.29 is relatively smaller possibly mainly due to the lower Reynolds number rather than higher Mach number. A simple nonlinear identification model was adopted and it seems that the results were improved to a little bit.