Semi-Empirical Unsteady Nonlinear Aerodynamic Model to Predict Transonic LCOCharacteristics of Fighter Aircraft

摘要

An analysis of steady wind tunnel data, obtained for a fighter type aircraft, hasindicated 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 was developed. Its preliminary version has been applied to several configurations and has correctly identified those which have encountered LCO. It has already shown the potential for application early in the design process of new aircraft to determine and understand the nonlinear aeroelastic characteristics. In the present paper this method is upgraded on the basis of results of unsteady wind tunnel force and pressure measurements obtained from an oscillating fighter type wings.