合成射流物理参数对控制翼型流动分离的影响

Effect of synthetic jets physical parameters on flow separation control over airfoil

应用计算流体力学(CFD)技术数值模拟了合成射流对NACA0015翼型流动控制的影响.合成射流施加的位置分别距离翼型前缘12%c、30%c和70%c(c为翼型的弦长),研究分析在不同位置施加合成射流,控制流动分离的效果随攻角和射流偏角的变化趋势,对组合射流的位置、相位角和动量系数进行研究.以二维不可压非定常Reynolds-averaged Navier-Stokes(RANS)方程模拟非定常分离流动,采用SST湍流模型,压力修正采用压力隐式算子分裂(PISO)算法,时间积分采用隐式处理方法,空间离散采用二阶迎风格式.通过对数值模拟结果的分析表明:1)12%c、30%c和70%c等对应的射流情形,采用切向射流均优于法向射流的控制效果;2)对于组合射流和单一射流,射流位置应靠近分离点或在分离点之前,才能达到流动控制的目的,射流位置越靠近分离点流动控制效果越佳;3)组合射流选择合适的相位角,可以增强流动控制的效果.

The effect of synthetic jets on controlling flow separation over a NACA0015 airfoil was numeri- cally analyzed using computational fluid dynamic （CFD） method. The synthetic jets were located at 12%c, 30%c and 70%c, respectively, from the leading edge （c is the chord length of the airfoil）. The trends of flow separation control effect at these locations with the variation of angle of attack （AOA） and jet angle were analyzed. Meanwhile, the locations, phase angle and momentum coefficient of multi-location synthet- ic jets were analyzed. The two-dimensional unsteady incompressible Navier-Stokes equations were used to simulate unsteady separated flows. SST turbulence model was utilized for the computation, and the pres- sure-implicit with splitting of operators （PISO） algorithm was utilized for pressure correction. An implicit numerical treatment was adopted for time integral and the second order upwind scheme for space discretiza- tion. The numerical results show that： 1） when synthetic jets are located at 12%c, 30 %c and 70%c from the leading edge, the tangential jet shows better control effect than normal jet; 2） for single and multi-lo- cation synthetic jets, the jet locations should be close to the separation point or prior to the separation point, only in this occasion can the purpose of flow control be achieved, and the closer the jet locations to the separation point, the better control effect can be expected; 3） the performance of multi-location syn- thetic jets can be improved by changing phase angle of multi-location synthetic jets.