Unsteady aerodynamic modeling at high angles of attack

An improved state-space representation for the unsteady aerodynamics of high angle of attack is presented here in this paper. The first order differential equations which was first given by Goman are used to model the dynamics of flow separation and vortex burst, meanwhile, some improvement considering the influence to the unsteady flow by the speed of the dynamic motion of the airframes. The aerodynamic coefficients are determined by the algebraic series in terms of input variables. The minimum mean-square error approach and maximum likely-hood method are used to identify the unknown parameters in the model the experiment data from the wind tunnel test. The unsteady aerodynamics models for the pitching up with constant rate to the high angle of attack and oscillating in pitching with large amplitude delta wing and the aircraft are built up here. The comparison of the results with the original model given by Gomam shows that the performance of the model is quite well and it is possible to be used for flight dynamic analyze of the aircraft.