Mode Switching Phenomenon on Variable Cant Angle Wingletted Wings

摘要

This work focuses on the fundamental physics of the flutter mechanism of a wing with a variable cant angle winglet. A numerical model using multibody flexible dynamics was developed to represent the structural component of the problem. The lift distributions along the span was modeled using strip theory. Both the structural and aerodynamic models were coupled to generate four dynamic aeroelastic equations that represent a continuous system. Those equations were used to model the system and perform an aeroelastic analysis. The results indicate that having a vehicle equipped with a variable cant angle winglet can increase flutter speed and expand its flight envelope. In addition, when a large winglet section at some cant angle is added, the second torsional mode of vibration becomes unstable and the first mode remains marginally stable. This phenomenon is known as mode switching.