An Introduction to Nonlinear Aeroelasticity

All the theoretical formulations presented so far are relative to the linear case and ideal inviscid subsonic flow. In practice there can be several nonlinearities coming from the fluid or from the structure or from both. The possibilities are truly endless, and a complete discussion is outside the scope of this presentation. One of the key concepts of nonlinear aeroelasticity is that there can be much more than “just” the flutter point. Actually, flutter may not be the end of the story, and an oscillation may be established (the so-called limit cycle oscillation, also named LCO by the commonly found literature). Another example of complicated interaction would be a moving shock wave interacting with a boundary layer. Nonlinear models will not be analytically discussed here. But some results will be shown as an introduction for the reader.