Research On Unsteady Aerodynamic Models At High Angle Of Attack And Longitudinal And Transverse Unsteady Aerodynamic Simulation Of Airplanes

In this paper, dynamic experiments of large amplitude motion are performed for background aircraft standard model in NH-2 low speed wind tunnel. Unsteady aerodynamic forces of the models are measured for the pitching motion of single degree?the coupled pitching and rolling motion?the rolling motion of single degree under different support angles of attack and the lateral coupled motion under 50 degree angle of attack. The unsteady aerodynamic characteristics of above motions are analysed.Using wind tunnel test results of the dynamic motion of the standard model as the sample data, the a& longitudinal aerodynamic model based on the angle of attack variation and the blateral aerodynamic model based on the sideslip angle variation are proposed. "Extrapolation" characteristics of the model is analysed. A method of linear "extrapolation" is proposed and verified by classic wind tunnel test data. On the above basis modeling method is improved. Unsteady aerodynamics math models of longitudinal motion and lateral motion of the standard model are completed.Using the mathematical model of unsteady aerodynamics, based on the sample data of the rolling motion of single degree, lateral unsteady aerodynamic force of the coupled pitching and rolling motion is calculated; based on the sample data of the pitching motion of single degree, longitudinal unsteady aerodynamic force of the coupled pitching and rolling motion is calculated; based on the sample data of the coupled pitching and rolling motion, unsteady aerodynamic forces of the pitching motion of single degree and the rolling motion of single degree under rotating flow field are calculated. The calculated results show good agreement with the test results, verifing the accuracy of the built mathematical models.