飞行器变后掠过程非定常气动特性形成机理

STUDY ON THE FORMATION MECHANISMS OF UNSTEADY AERODYNAMIC CHARACTERISTICS OF MORPHING FLIGHT VEHICLE IN SWEEP-VARYING PROCESS

可变体飞行器变后掠过程中的时变气动力与力矩特性对于飞行安全具有重要意义,是亟待深入研究的基础问题.通过风洞实验对其开展了研究,揭示了可变体飞行器变后掠引起的气动特性动态迟滞现象及滞回环大小与方向的影响因素.基于风洞实验结果和力学中一些重要概念,提出了3种物理效应:流场迟滞效应、附加运动效应、固壁牵连效应,以此定性与定量论证了可变体飞行器变后掠过程中非定常气动特性的形成机理.除了能解释实验现象,这一机理研究亦可用于后续可变体飞行器变后掠过程中的气动特性建模.

Time-dependent aerodynamic forces and moments of morphing aircraft during sweep-varying process are important to flight safety, and hence need thorough investigations. This paper conducted a wind tunnel experiment of morphing aircraft and analyzed the aerodynamic characteristics. The results demonstrate the dynamic hysteresis caused by sweep-varying, and various factors that affect the magnitude and director of hysteresis loop. Based on these results and some important concepts in mechanics, three physical effects, i.e., flow-field hysteresis effect, additional motion effect and wall implication effect, were proposed in order to interpret the formation mechanisms of the unsteady aerodynamic characteristics of morphing aircraft. This investigation about mechanisms can be used to further study on modeling of aerodynamic characteristics.