Reduced-Order Aerodynamic Model and Its Application to a Nonlinear Aeroelastic System

Limit Cycle Behavior of an Airfoil With a Control Surface

“…A schematic of the typical airfoil section with a control surface at the trailing-edge of the main wing is shown in Figure 1(a) and a freeplay nonlinearity in the structural stiffness of the control surface is shown in Figure 1 (b). Results obtained from the direct time integration of the nonlinear equations were shown by Tang et al (1998) to be in good agreement with previous theoretical and experimental work of Conner et al (1997).…”

“…The numerical results can be given a simple and interesting physical explanation that is confirmed by the time simulation of the nonlinear equations. The present study is a continuation and extension of Tang et al (1998).…”

“…B K , B and B are aerodynamic coefficient matrices arising from the aerodynamic model, and M C , C C , K C are equivalent mass, damping and stiffness matrices arising from the structural and aerodynamic models. More details of this aerodynamic modeling can be found in Tang et al (1998).…”

“…Based on the nonlinear structural model presented in Conner et al (1997), a reduced-order finite-state aerodynamic model based upon Peters' finite-state model, presented in Peters & Cao (1995) for the two-dimensional aerodynamic flow over an airfoil, has been applied to this nonlinear aeroelastic system in Tang, Conner & Dowell (1998). Using a small number of these aerodynamic eigenmodes (i.e.…”

Limit cycle oscillations of a complete aircraft

“…This is very much computer time intensive and one needs to select a set of initial conditions relevant to the problem at hand. Tang et al(1998) used a reduced-order, finite-state inflow model to analyze the nonlinear behavior of airfoil sections with free play nonlinearities. Tang and Dowell (1993) have analyzed the nonlinear behavior of a flexible rotor blade due to structural free-play and aerodynamic stall nonlinearities.…”