翼型气动优化设计问题多极值特性研究

认识翼型气动外形优化问题设计空间的多极值特性,有助于人们在翼型设计阶段选择合理的优化算法,提高优化效率、缩短设计周期。研究RAE2822 翼型在优化减阻过程中设计空间的多极值特性,采用ADODGcase2算例,使用自由变形方法(FFD)对翼型进行参数化,通过拉丁超立方抽样方法对翼型加入初始扰动;使用基于梯度的优化算法对经过不同扰动后的翼型进行优化,并将优化结果与全局优化算法的优化结果进行对比。结果表明:ADODGcase2可能是一个单峰值气动设计问题,梯度算法能够得到相对满意的最优解,并且具有更高的优化效率;在给定面积约束的条件下,对于翼型跨声速单点减阻优化问题,设计空间很可能是单峰值的,可直接使用梯度优化算法。

Mutiple Local Minima Characteristics of Airfoil Aerodynamic Design Optimization Problem

This paper explores the multiple local characteristics of the RAE2822 in the process of minimising drag optimization. AIAA Aerodynamic Design Optimization Discussion Group(ADODG) case 2 is used. The airfoil is parameterized by using the FFD (free-form deform) parameterization technique, and the initial perturbation is added to the airfoil by using the uniform latin hypercube method. Then the gradient-based optimization algorithm is used to optimize the airfoil after different disturbances, and the optimization results are compared with the optimization results of the global optimization algorithm. The results show that ADODG case2 is a convex peak design problem. The gradient-based algorithm can obtain a relatively satisfactory optimal solution and has a higher optimization efficiency. The conclusion can be inferred from this study that airfoil transonic minimising drag optimization subject to area constraint is possible a convex peak design problem. Gradient optimization algorithms can be used directly.