飞翼布局无人机流动分离控制及机理分析

ACTIVE SEPARATION CONTROL FOR THE FLYING-WING UAV USING SYNTHETIC JET

以小展弦比飞翼式无人机为对象,开展了基于零质量射流的主动流动控制数值模拟研究.比较分析了应用零质量射流前后飞翼式无人机纵向气动特性的改善效果,并通过流场特征的分析探讨了流动控制技术产生气动增益的原因.研究结果表明在模型中等迎角、大迎角范围,零质量射流技术可以显著增加升力系数,最大幅值达25%,并且拓宽了纵向力矩的线性范围.机理分析表明,零质量射流扰动通过提高模型绕流场的边界层掺混,增强附面层内外的动量输运,使得附面层有足够的能量克服逆压梯度和黏性损耗,从而达到减缓流动分离甚至使分离流再附的目的.

The numerical simulation is conducted on the low-aspect-ratio flying-wing UAV model based on synthetic jet technology. Effectiveness of the synthetic jet active flow control technique for improving the longitudinal aerodynamic characteristics of model at low speed is explored and validated. The actuators produced significant shifts in the lift curve up to 25%. The flow characteristics analyses reveal that the disturbance caused by synthetic jet can transfer the higher moment flow to the boundary layer and reenergized the unstable boundary layer. The numerical results show that the synthetic jet technology can effectively improve flow separation at the middle and high angle of attack flight conditions.