Robust design of NLF airfoils

• Published in: Chinese journal of aeronautics 2013-04, Vol.26 (2), p.309-318
• Main Authors: Li, Jing, Gao, Zhenghong, Huang, Jiangtao, Zhao, Ke
• Format: Article
• Language: English
• Subjects: Aerodynamic characteristics; Airfoils; Computer simulation; Design engineering; Free form deformation; Mathematical models; Navier-Stokes equations; Navier-Stokes方程; NLF airfoils; NURBS; Optimization; Parametrization; Particle swarm optimization (PSO); Robust design; Surrogate model; Transition model; 优化设计方法; 层流翼型; 稳健设计; 空气动力特性; 粒子群优化算法; 非均匀有理B样条
• ISSN: 1000-9361
• DOI: 10.1016/j.cja.2013.02.007

A robust optimization design approach of natural laminar airfoils is developed in this paper. First, the non-uniform rational B-splines （NURBS） free form deformation method based on NURBS basis function is introduced to the airfoil parameterization. Second, aerodynamic characteristics are evaluated by solving Navier-Stokes equations, and theγ-Reθt transition model coupling with shear-stress transport （SST） turbulent model is introduced to simulate boundary layer transition. A numerical simulation of transition flow around NLF0416 airfoil is conducted to test the code. The comparison between numerical simulation results and wind tunnel test data approves the validity and applicability of the present transition model. Third, the optimization system is set up, which uses the separated particle swarm optimization （SPSO） as search algorithm and combines the Kriging models as surrogate model during optimization. The system is applied to carry out robust design about the uncertainty of lift coefficient and Mach number for NASA NLF-0115 airfoil. The data of optimized airfoil aerodynamic characteristics indicates that the optimized airfoil can maintain laminar flow stably in an uncertain range and has a wider range of low drag.