MODELING NONLINEAR HIGH-PRECISION UNSTEADY AERODYNAMICS FOR ADVANCED AIRCRAFT AT HIGH ANGLE OF ATTACK

摘要

An accurate unsteady aerodynamics model at high angle of attack has an important significance to evaluate the flight characteristics of advanced flight vehicle with high maneuverability. Based on high-precision SAS numerical method, the effects of pitch rate, reduced frequency and amplitude on unsteady aerodynamics at high angle of attack have been detailed analyzed, then the factors are extracted to modify the traditional state-space model and a new state-space representation for unsteady aerodynamics up to stall range is proposed. The Particle Swarm Optimization algorithm is used to identify the unknown parameters in the model from static and dynamic CFD results. The new model and method are demonstrated by using the CFD data of a 70 degree delta wing. The results show that it is possible to analyze the unsteady aerodynamic problems in high angle of attack regime for the advanced aircraft.