Accession Number : ADP007814

Title :   Development of a Method to Predict Transonic Limit Cycle Oscillation Characteristics of Fighter Aircraft,

Corporate Author : NATIONAL AEROSPACE LAB AMSTERDAM (NETHERLANDS)

Personal Author(s) : Meijer, J. J. ; Cunningham, A. M.

Report Date : MAR 1992

Pagination or Media Count : 21

Abstract : An analysis of steady wind tunnel data, obtained for a fighter type aircraft, has 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 has been applied to several configurations and has 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 non-linear 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 will be described in its present form and results of the latest predictions will be compared with flight test trends and used to further assess various parametric effects.

Descriptors :   *SHOCK, *FLOW SEPARATION, *AIRCRAFT MODELS, AERODYNAMICS, CONFIGURATIONS, CYCLES, DIFFERENTIAL EQUATIONS, EDGES, FLIGHT, MEASUREMENT, MODELS, PREDICTIONS, PRESSURE, TEST AND EVALUATION, TRAILING EDGES, VELOCITY, WIND TUNNELS, NETHERLANDS, WIND TUNNEL TESTS, FIGHTER AIRCRAFT.

Subject Categories : Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE