飞翼布局低速反弯翼型稳健优化设计

Low speed reflexed airfoil robust optimization design for flying wing configuration

以动压、雷诺数的变化和外形的制作误差与变形作为低速反弯翼型飞翼布局小型无人机设计中的不确定性因素,以降低翼型气动特性对这些不确定因素的敏感性为目标进行稳健设计。在稳健模型的计算中,为了量化外形误差,采用改进的PARSEC方法进行翼型的参数化,为了节省计算资源和时间,采用神经网络响应面代替N-S方程求解,为了使不确定性因素对翼型性能的影响得到真实反映,采用蒙特卡罗随机实验模拟代替目标变量概率分布函数计算。对Epler186翼型的稳健设计结果表明,模型和计算方法可行且高效,可有效降低翼型对不确定因素的敏感性。

In this paper,the uncertain factors which should be taken into consideration at the very beginning of reflexed airfoil design for a low speed flying wing mini UAV were specified as the variation of dynamic pressure and Reynolds number,together with the distortion and manufacture error of physical shape,then a robust design model was advanced to degrade the performance sensitivity to these uncertain factors.During the process of robust model computation,a parametrization technique based on the improved PARSEC was employed to quantify the uncertain of airfoil physical shape,a neural network was trained to predict the aerodynamics performance instead of the solver of Navier-Stokes Equation,and Monte Carlo random experimental simulation was used to substitute the calculation of objective＇s probability density function.The optimization result of the Epler186 proves that this robust model and the computation method are effective and applicable,and the sensitivity of airfoil performance to the uncertain factors could be reduced efficiently.