Development on Unsteady Aerodynamic Modeling Technology at High Angles of Attack

Abstract

Directly obtaining the dynamic values of the unsteady aerodynamics at large angle of attack by either the CFD or experimental technologies to present further analysis should pay great costs. Therefore, the unsteady aerodynamic modeling based on a few calculations or experimental data has been established and developed. This study mainly discusses the development and challenges of unsteady aerodynamic modeling of aircraft at high angle of attack, investigates the accuracy, efficiency, and future development of the conventional and modern intelligent models divided according to the established physical basis. The conventional methods have been built on valuating changing law of either the macroscopic aerodynamic performance or microscopic flow separating characteristics, which is mainly composed of linear/nonlinear aerodynamic derivative model, integrated models, differential models, aerodynamic incremental model and angular rate model. The intelligent methods are represented by fuzzy logic, support vector machines and shallow / deep neural network models, all of which are proposed by training the sample data based on various intelligence algorithms. Compared to the conventional aerodynamic models, these intelligent models have strong generalization ability and high predication efficiency. However, they are poorly interpretable due to the lack of physical basis on the dynamic flow fields. In general, the future unsteady aerodynamic models should be developed by focusing on the intelligently characterization of physical meaning of the nonlinear dynamic flow fields to improve the predication accuracy and efficiency on the complex aerodynamic forces/moments, and the applications in aircraft design and flight dynamics.