变形体超临界翼型动态气动特性

Unsteady aerodynamic characteristics of deformable supercritical airfoil

为实现飞行器外形根据来流条件变化做出相应调整,需深入了解变形体非定常气动现象和机理。以典型超临界翼型为研究对象,分别制定了翼型厚度及弯度变形方案,实现了翼型柔性变形。利用数值仿真方法在高雷诺数条件下开展了翼型厚度、弯度连续变形带来的非定常效应。结果表明,翼型厚度、弯度连续变形均会形成明显的升、阻力系数迟滞环,且频率越高、幅度越大,变形导致的非定常效应也越强;相对而言,翼型弯度变形产生的非定常效应较厚度变形产生的非定常效应更明显。最后通过分析流线图及压力系数分布图发现,流动结构随几何变形的迟滞性会导致非定常效应的产生。

People hope that aircraft shape can adjust according to the change of flow condition, thus it is essential to learn about the unsteady aerodynamic phenomenon and mechanism of deformable aircrafts. Then the deformation vehicle performance can be improved, and the safety of flight can be ensured. In this paper, supercritical airfoil was focused on, and airfoil thickness and camber deformation schemes were designed, respectively. Numerical simulation method was used to simulate the unsteady effect due to the airfoil thickness or camber deformed in high Reynolds number condition. The results show that the unsteady effect is strong with distinguishable lift and drag hysteresis loops. In addition, as the deformation frequency and amplitude increase, the unsteady effects are significantly strengthened. The unsteady effect resulted from the camber deformation is relatively stronger than that from the thickness deformation. Finally, by analysing the flow streamline and pressure coefficient distribution, the unsteady effects with geometric distortion can be produced by the hysteresis of the flow structure, such as the strength and location of shock, and the boundarv layer separation.