斜出口合成射流控制机翼分离流实验研究

摘要

采用倾斜出口合成射流激励器对NACA633-421三维直机翼进行分离流主动流动控制，天平测力结果表明合成射流可以有效地控制机翼流动分离，提升最大升力系数10．4％，推迟失速迎角4°。运用边界层测试技术及粒子图像测速系统（PIV）对合成射流分离流控制机制进行研究分析，结果表明，控制后边界层速度型变得“饱满”，形状因子减小，其底层能量增加，抵抗逆压梯度能力增强。瞬态及时均化PIV测试流场图进一步证明合成射流向主流进行动量注入及掺混后，主流附着机翼表面，翼面附近流体湍流动能和雷诺剪切应力增加，分离点向下游推迟，流动分离得到抑制。%Active flow control on a three-dimensional NACA633-421 airfoil has been investiga-ted experimentally using beveled-slit-synthetic-j et-actuator (BSSJA).Balance force measurement results show that the synthetic jet can control the flow separation effectively,improve the maxi-mum lift coefficient by 10.4% and increase the stall angle of attack by 4°.Both boundary layer velocity measurement and particle image velocimetry (PIV)technology have been performed un-der selected experimental conditions to investigate the mechanism of synthetic jet flow control. Results reveal that the shape factor of boundary layer velocity profile decreases with BSSJA con-trol and the promotion of the power of the boundary layer is responsible for the control effect. The instantaneous flow maps and ensemble-averaged PIV results reveal that synthetic j et tends to enhance the flow dilution and transfer the mass flux so that the separated flow could attach to the wall of NACA633-421 airfoil again.In addition,the turbulent kinetic energy (TKE)and Reyn-olds stress are increased near the wall compared to the situation without control.