利于翼型优化设计的超临界翼型参数化方法

为减少超临界翼型优化中的设计变量,消除优化结果的不光顺现象、保证C₂连续,在优化过程中控制翼型几何特性的变化范围,设计出了由4条首尾相接的有理Bézier曲线表示的超临界翼型的翼型参数化方法,该方法对翼型数据的参数化过程中主要运用了Bézier曲线拟合算法与SPSA(Simultaneous Perturbation Stochastic Approximation)优化算法,并在Bézier曲线拟合算法中使用了有别于常用方法的数据点参数选择方法.将这种超临界翼型参数化方法与优化算法结合便可实现翼型优化设计,其中的设计变量为21个,优化结果不仅光顺且满足C₂条件,通过设定设计变量变化范围便可控制相应的翼型前缘半径、上下弦最高最低点的位置与曲率、尾部契角等几何特征.

Supercritical airfoil parameterization method feasible to optimum design

To reduce the number of design variables in the supercritical airfoil optimization, eliminate the unfairness phenomenon, ensure C₂ condition, control the geometric characteristics of the airfoil in the optimization process, a parameterization method for supercritical airfoil based on four rational Bézier curve was presented. In the parametric process to the airfoil data, the Bézier curve approximation algorithm and SPSA(simultaneous perturbation stochastic approximation) algorithm were used and in the Bézier curve approximation algorithm the way to choose the parameter to the data points is different from the common method. Supercritical airfoil shape optimization can be achieved by combining this method with optimization algorithms. It contents 21 design variables, the optimization result is fair and satisfies the C₂ condition, the geometric characteristics of the airfoil such as leading edge radius, upper and lower crest location including curvature there, the boattail angle can be controlled in the optimization process by setting the range of the design variables.