不同孔口构型合成射流激励器的低速翼型分离控制特性

为探索孔口构型对合成射流激励器流动控制效果的影响，采用数值方法研究了4种不同孔口构型的合成射流激励器对大攻角20。下NACA0015翼型分离流动的控制特性。通过对翼型气动力特性、脱落旋涡结构以及射流孔口附近流动结构的分析，阐述了合成射流的边界层分离控制机理。首先在距离翼型前缘10％、20％、30％弦长位置安装激励器进行数值模拟，得到20％弦长的激励器方案效果最好。然后在此位置处，采用设计出的“凸台型、凹台型、斜出口”以及常规平台型等4种孔口构型的激励器进行流动分离控制。结果表明，在所有方案中，流动控制效果最佳的方案是喷口向流动方向倾斜的孔口构型；在这种方案下，射流与主流掺混使得边界层的动能增大，抗反压能力增强，并且由于喷出的气流方向与主流方向夹角很小，掺混后的气流流动方向与主流相近，从而使得边界层分离被大大削弱甚至消失。

Separation control characteristics of different configurations of orifice synthetic jet actuators used in low-speed airfoil

Numerical method is used to study the control characteristics of synthetic jet （SJ） actuator with four different orifice de- signs over NACA 0015 airfoil. By analyzing the airfoil aerodynamic characteristics and vortex structure, the synthetic jet bounda- ry layer separation control mechanism is discussed. Firstly, the synthetic jet is applied to 10%, 20%, 30% chord length away from the leading edge of the airfoil, respectively. The results show that 20% chord length is the best installation location. Then, the boundary layer characteristics are analyzed for the airfoil with synthetic jet on this best location. For the four kinds of SJ ori- fice designs considered, the best option is vent orifice inclined to the direction of flow. In this best case, the mixing between jet and mainstream leads to the increase of boundary layer kinetic energy, so the anti-pressure ability is strengthened. Moreover, there is a small angle between the blowing jet and the mainstream, which makes a similar direction of mixed flow to the main- stream, so that the boundary layer separation is greatly weakened.