基于CST参数化方法的翼型气动优化设计

Aerodynamic Optimization Design of Airfoil Based on CST Parameterization Method

翼型参数化方法的优劣对最终优化设计结果有着非常重要的影响,它是决定优化设计效率和最终优化效果的关键因素。针对翼型外形的不同表达方式(分为翼型直接CST、扰动CST和中弧线叠加厚度分布CST等),分别发展了相应的CST参数化程序,并将其应用于翼型气动优化设计,研究几种不同参数化方式的优化结果和优化效率。RAE2822翼型单目标减阻优化设计的研究表明,基于CST的三种参数化方法和基于Hicks-Henne函数的参数化方法的减阻效果相当,但计算时间相差很大。在设计变量数相当的情况下,扰动CST方法和中弧线叠加厚度分布CST方法的设计效率高于直接CST参数化方法和Hicks-Henne参数化方法而中弧线叠加厚度分布CST的优化效率略高于扰动CST。DU93-w-210翼型单目标最大升阻比优化设计的研究进一步说明中弧线叠加厚度分布CST的优化效率略高于扰动CST。

Airfoil parameterization method has a very important impact on final optimization result. It has significant influence on the optimization design efficiency and result. In this paper, CST （Class function/Shape function Transformation） method is introduced to describe the airfoil shape with different geometrical parameters： direct CST, perturbed CST, and mean camber and thickness distribution CST. These parameterization methods are ap- plied to airfoil optimization and the corresponding design results and efficiency are compared with each other. Drag minimization of a transonic airfoil is studied, by using the direct CST method, the perturbed CST method, the mean camber and thickness distribution CST method and the Hicks-Henne parameterization method for different orders. The results show that, the above four parameterization methods have nearly identical drag reduction effect but the respective computational costs are quite different. The perturbed CST and mean camber and thickness distribution CST are more efficient than the direct CST method and Hicks-Henne parameterization method with almost equivalent number of design variables. To further compare the optimization effect of the perturbed CST and mean camber and thickness distribution CST under fourth order Bernstern polynomial, lift drag ratio maximization of a wind turbine airfoil is studied. The results and their analysis show preliminarily that mean camber and thickness distribution CST appears appreciably more efficient than the perturbed CST.