可变展长机翼非定常气动特性数值研究

为探索可变展长机翼变形过程中的非定常气动特性及其机理，以ONERA M6机翼为模型，利用动网格技术对其进行了非定常气动特性研究.研究表明:在机翼连续变展长过程中，非定常气动特性曲线以滞回环的形式围绕着相应的准定常曲线；变形周期、攻角和来流马赫数对滞回环有一定影响，但与准定常气动特性相比，单纯的展长变化引起的非定常气动效应并不明显；在一定的计算条件下，非定常升力系数偏离其相应的准定常升力系数的最大值不足2%；可变展长机翼非定常气动特性产生的主要原因在于流场结构迟滞.同时，由于流场结构迟滞效应比较微弱，可变展长机翼的非定常气动特性不显著. 

Numerical Investigation on Unsteady Aerodynamic Characteristics of Variable-Span Morphing Wing

In order to explore the unsteady aerodynamic characteristics and the mechanism of morphing wing during span-varying process, numerical simulations were conducted for a model of ONERA M6 wing based on dynamic mesh technology, and its unsteady aerodynamic characteristics were studied. The results show that, as the hysteresis loops, the unsteady aerodynamic characteristics curves of morphing wing during shape morphing are surrounding the corresponding quasi-steady curves; that morphing period, angle-attack and stream Mach number have some influences on the loops. But compared with the corresponding quasi-steady, the unsteady aerodynamic characteristics caused by variable span are not significant; under certain numerical condition, the maximum of unsteady lift coefficient deviation from the corresponding quasi-steady is less than 2%. The main reason of the above unsteady aerodynamic characteristics is flow field structure hysteresis. Meanwhile, the unsteady aerodynamic characteristics of variable-span morphing wing are not significant due to the weak flow field structure hysteresis.