Development of a Method to Predict Transonic Limit Cycle Oscillation Characteristics of Fighter Aircraft (Continued)

摘要

An analysis of steady wind tunnel data, obtained for a fighter type aircraft, has indicated that shock-induced and trailing-edge separation play a dominant role in the development of Limit Cycle Oscillations (LCO) at transonic speeds. On the basis of these data a semi-empirical LCO prediction method is being developed. Its preliminary version has been applied to several configurations and has correctly identified those which have encountered LCO. It has shown already the potential for application early in the design process of new aircraft to determine and understand the nonlinear aeroelastic characteristics. The method has been upgraded since. It will be described in its present form and results of the latest predictions will be used to further assess various parametric effects. The ultimate refinements are expected from recent unsteady wind tunnel force and pressure measurements of which a few preliminary results are analyzed.