两种有翼飞行器高超声速动态气动特性的对比实验研究

Comparative experiments of two kinds of space shuttle like model for hypersonic pitching damp by model free flight technology

采用模型自由飞技术在脉冲型高超声速风洞中测量了两种类航天飞机外形模型的俯仰阻尼导数。两种模型具有十分接近的外形特征尺寸和投影面积 ,但机身和机翼的剖面则彼此各不相同。实验在名义马赫数M∞ =6.4条件下进行 ,同一名义实验条件下的重复实验显示一致的运动形态和接近的动导数测量结果。气动参数辨识采用最大似然法 ,对风洞实验准定常试验时间中模型的平面运动以线性气动参数模型辨识得到它们的俯仰阻尼导数。结果揭示两种外形有差异的模型呈现迥然不同的动态气动特性 :带OMS舱的航天飞机仿真模型具有动态稳定性 ,而简化外形的类航天飞机模型则为动不稳定。虽然对导致这种极大差异的直接物理原因还有待深入研究 。

Model free flight experiments were carried out in impulse hypersonic wind tunnel at Institute of Mechanics, Chinese Academy of Sciences to obtain pitching damp of two space shuttle models. The shape and project area of these two kinds of models are almost the same but the profiles of body and wings are different. The model free flight movements were recorded by synchronized high speed photography. The pitching damps of models were obtained by parameter identification using maximum likelihood method. The repeated experiments showed that under same experimental condition models moved with same pattern and had close pitching damps. The results show that these two kinds of space shuttle models with different profile have sharply different dynamic characteristics. The simplified space shuttle models (Model A) are all dynamically unstable and the space shuttle with OMS (Model B) are all dynamically stable. The mechanism of this phenomenon still needs to be studied further, but the results obviously show that the dynamic characteristics of these space shuttle like vehicles are sensitive to their geometries of body and wings in detail.