What causes aerodynamic flutter?

Aeroelastic flutter involves the unfavorable interaction of aerodynamic, elastic, and inertia forces on structures to produce an unstable oscillation that often results in struc- tural failure. High-speed aircraft are most susceptible to flutter although flutter has occurred at speeds of 55 mph on home-built aircraft.

This flutter is caused by the coalescence of two structural modes – pitch and plunge (or wing-bending) motion . This example wing has two basic degrees of freedom or natural modes of vibration: pitch and plunge (bending). The pitch mode is rotational and the bending mode is a vertical up and down motion at the wing tip.

Flutter is a self-excited vibration of the wing of an aircraft around which air is flowing . It is caused by an interplay of aerodynamics and elastic forces as well as by inertial forces. Flutter can result in damages to the structure, possibly even leading to a crash.

Different types of aeroelastic effects are commonly distinguished from each other. They include vortex-induced vibration, galloping, flutter, and aerodynamic damping . where m is the mass per unit length of the structure.