Research On Aircraft Unsteady Aerodynamics Modeling And Flight Simulation At High Angles Of Attack

This thesis mainly studied the unsteady aerodynamic characteristics at high angles of attack from two aspects. The first part is the modeling of aircraft nonlinear and unsteady aerodynamics, The second is the flight simulation of aircraft maneuvering characteristics using the aerodynamic model. In addition, briefly introduces the wind tunnel test technology.For the first part content, based on the experimental data of longitudinal pitch motion and one degree of freedom yaw, roll and their coupling oscillations tested at 40 degrees of support angle in the NH-2 wind tunnel, through the model identification, the state space model based on maximum likelihood method and RBF neural network model are established, both of them have a good agreement with the measured harmonic and slope movement data. In addition, using the "in-phase" and the "out-of-phase" derivatives of the aerodynamic coefficient for pitch motion and dynamic test data of a delta wing, the state space model based on two-step linear regression method is established, also compared with the experiment data and verified the accuracy of the model. It shows that the established three models can describe the nonlinear and unsteady aerodynamic characteristics.For the second part, the 6 DOF equations was used in the MATLAB\SIMULINK to simulate the flight characteristics with the aerodynamic obtainded from the unsteady aerodynamic model term obtained in this article plus the F-16 conventional dynamic derivative term, the simulation results are close to F-16 flight test aerodynamic characteristics.It shows that, the plane is stable and movement variables gradually converge at small incidence flight, but the lateral-horizontal movement parameters at high angles of attack are not decaying with time, because of the roll damping is positive, roll motion is divergence, then brought the increase of yaw oscillation, this is similar to the lateral-directional oscillating of F-16 configuation appeared at flight test.