Surrogate-based aerodynamic shape optimization with application to wind turbine airfoils

Design of airfoils specially tailored for wind turbine blades has dramatic influence on the performance of a wind turbine. The traditional way for wind turbine airfoil design is a kind of trial and error process. In order to improve the design efficiency was well as the performance of the design, numerical optimization methods coupling optimization algorithm with CFD codes in an automatic process chain are of great interest. This study is focused on the development of efficient numerical optimization design methods for wind turbine airfoils. The main feature is to use surrogate-based optimization. Surrogate-based optimization is very efficient and has the capability of finding global optima; it can be classified as the third-type optimization method other than the traditional gradient-based methods and gradient-free searching methods, such as evolutional algorithms. Optimization designs of FFA-W3-211, inverse design of NPU-WA-300 and realistic numerical optimization of NPU-WA-250 are exercised. Examples show that the developed methods are efficient and robust, with sufficient flexibility of handling both geometric and aerodynamic constraints, multi-points design and multi-objective design.