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 semiempirical 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 on oscillating fighter type wings. In particular, an aerodynamic nonlinear state-space model embedded in the LCO prediction method will be demonstrated. The developed aerodynamic model is a semi-empirical, unsteady, nonlinear model which makes use of these experimental steady and unsteady data. Validations are presented for various fighter configurations by comparing calculated LCO results with information from flight test data.
Parametric Identification of Transonic Unsteady Flow Characteristics for Predicting Flutter of Fighter Aircraft with External Stores
1996
16 pages
Report
Keine Angabe
Englisch
Aircraft , Aerodynamics , Aerodynamic characteristics , Aircraft configurations , Flutter , Oscillating flow , Parameter identification , Prediction analysis techniques , Transonic flow , Unsteady flow , External stores , Fighter aircraft , Flow characteristics , Separated flow , Wind tunnel tests , Wings , Foreign technology
British Library Conference Proceedings | 1996
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