Research on variable camber wing of civil aircraft considering buffeting characteristics

Variable camber trailing edge technology can be used for improving the buffeting characteristics of a wing at a large lift coefficient. Thus, it is of great importance to change the overall performance of a civil aircraft. Aiming at solving this problem, a smooth, continuous, and differentiable separation function is developed to describe quantitatively the evolution of separation caused by the shock wave boundary layer interaction. Also, a new buffering characteristic evaluation method suitable for aerodynamic optimization is realized based on the separation function. A typical civil aircraft configuration is selected to optimize the drag reduction considering buffeting performance. The results show that flow separation caused by the shock wave boundary layer interaction can be reduced, and the drag reduction of 1.89% can be achieved by using variable camber design variables on the trailing edge at 1.3g buffeting point. The optimization by using the drag of cruise point as an objective resulted in a high-pressure recovery under cruise condition and low-pressure recovery at 1.3g point. Thus, the strength of separation and impact of buffeting performance constraints on design points are reduced. Finally, the optimization resulted in a drag reduction of about 1% with pitching moment trim constraints. Therefore, the aerodynamic optimization design method combined with the separation function to predict buffeting characteristics can be used to optimize the design of a variable camber wing and provide more practical reference value to design improvement. © 2020, Science Press. All right reserved.