Airfoil Optimization With Isogeometric Collocation Based On Potential Flow Model

Airfoil design is very important for shape design of aircraft and study on aerodynamic.In order to shorten the development period and reduce the research cost,studying the optimization design method based on numerical computation of airfoil aerodynamic performance becomes the focus of recent researches.In this paper,a method for construction of airfoil based on the IGA-C and the potential flow model is presented.Firstly,on the basis of analysis of the actuality and significance of airfoils and IGA,the potential flow model is solved in incompressible ideal fluid based on the IGA-C.Then we introduce the geometrical properties of airfoils.The potential flow model is computed with IGA-C,which provides the aerodynamic characteristics with blade element theory.At last,objective function including lift-drag ratio and fitting term is constructed to result the optimal airfoil.The smoothness and continuity are both the criteria for the evaluation of the resulting airfoil.In order to acquire the initial airfoil for the optimal airfoil’s solution,we fit the data of airfoil using PIA and represent airfoil with a cubic NURBS curve defined over non-uniform knot vector,and then consider the maximum ratio of lift to drag and minimum fitting term as the objective function to obtain the optimal airfoil’geometric configurations and aerodynamic characteristics by Gradient Descent Method and Genetic Algorithm.The experiments demonstrate that the presented method based on the IGA-C and the potential flow model performed well for some typical airfoils.The resulting curve is smooth and it keeps airfoil’s own identity such as supercritical aerofoil profile.What’s more,there is better performance of airfoil function compared with some classical airfoils,which is used for the airfoil optimization design.