三角翼作俯仰运动时水洞测力和流动显示实验研究

Force measurement and visualization experimental investigation on a pitching delta wing

基于水洞中三角翼模型的动态测力和流动显示实验,讨论了俯仰运动的起始角、运动幅度和运动速率对三角翼俯仰运动时的气动特性和流动结构的影响。三角翼的气动力在俯仰运动中会产生“迟滞”或“过冲”现象。中等攻角以上,上仰运动推迟了三角翼的失速,大幅度增大了三角翼的升力系数。俯仰运动起始角和运动幅度的影响大小与其对应的静态三角翼流态有关,三角翼在涡破裂流态和完全分离流态之间作俯仰运动时,上仰时升力系数将始终高于下俯时的升力系数,运动中存在显著迟滞。迟滞的大小也受俯仰速率的影响。

Force measurement and visualization experiments were conducted on a pitching delta wing to investigate the effects of starting angle of attack, pitch range, and pitch rate on dynamic aerodynamics and flow structure of the delta wing. A hysteresis loop appears during pitching. When angle of attack is above moderate angle, pitch-up maneuver delays stalling, and increases maximum lift coefficient much. The strength of the effects of starting angle of attack and pitch range is related to corresponding flow structure of static delta wing. While the delta wing pitching between vortex-breakdown flow and full-separation flow, lift coefficient during pitching up is always greater than that during pitching down, and the hystere- sis loop is obvious. The strength of hysteresis loop is also affected by pitch rate.