ESDU 84020 explains the derivation and application of the indicial (step-response) functions (also called Wagner and Kussner functions) used to study aircraft response. The functions are introduced through the Fourier integration of the frequency-dependent generalised airforce coefficients associated with oscillatory motion. Indicial functions for use in predicting response in lift and pitching moment due to heave or pitch rate@ or deflection of a 20 per cent chord control@ are tabulated for thin aerofoils in subsonic and supersonic flows. Results obtained for a range of typical airframe two- and three-dimensional geometries@ including wing/tailplane combinations@ again through the speed range to supersonic@ are illustrated graphically. They include the effects of active controls. The results are discussed and various aspects of the mathematical modelling of unsteady flows are highlighted.
ESDU 84020-1984 history
1984ESDU 84020-1984 An introduction to time-dependent aerodynamics of aircraft response@ gusts and active controls.