小展弦比薄机翼精细化气动优化设计研究
摘要
For aerodynamic design of figher wings with the feature of small aspect ratio, the plat shape, camber-twist and thickness modification are mainly concerned and refined design of the airfoil is neglected. Therefore, Euler equation combined with boundary layer is the main technique to calculate the aerodynamic characteristics. Taking a typical fighter wing as an example, Euler equation and RANS equation are respectively utilized to calculate the flow field of the figher wing. From the result, the flow details cannot be captured by Euler equation which reveals that Euler equation is not qualified for refined design of figher wing. Airfoil aerodynamic design optimization is carried out and it is inferred that the results of airfoil design does not hold in small aspect ratio wing. Therefore, for small aspect ratio wing, airfoil design optimization must be conducted in 3-D circumstance. A 3-D aerodynamic design optimization frame is built which consists of FFD parameterization method, robust mesh deformation technique, Kriging surrogate model and PSO optimization algorithm. Employing the optimization frame, a single objective design is carried out at transonic state and a multi objective design is conducted at transonic/supersonic states. Aerodynamic characteristics are greatly improved from the design results.