An analysis of steady wind tunnel data obtained for a fighter type aircraft indicated that shock-induced and trailing edge separation plays a dominant role in the development of Limit Cycle Oscillations (LCO) at transonic speeds. On this basis, a semi-empirical LCO prediction method is being developed which makes use of such steady wind tunnel data. The preliminary method was applied to several configurations and correctly identified those which have encountered LCO. The method has the potential for application early in the design process of new aircraft to determine and understand these nonlinear aeroelastic characteristics. The method is still being evaluated, and upgrading and refinements are expected from unsteady wind tunnel force and pressure measurements to be obtained from oscillating models as part of an extensive investigation into the aerodynamic nature of LCO. The method is described in its present form and the results of the latest predictions are compared with flight results and used to further assess various parametric effects.
Development of a Method to Predict Transonic Limit Cycle Oscillation Characteristics of Fighter Aircraft
1992
21 pages
Report
No indication
English