Stability Analyses of a Foil with an Active Trailing-edge Flap

The aeroelastic fluttering response is a standard feature of airfoils in many different applications such as aero-vehicles, renewable energy extraction, and animal locomotion. Often, to enhance the performance and increase the reliability of a particular system, the fluttering response should be suppressed or controlled. In this work, we investigated how the active flap can be utilized to modify the flow around the airfoil and thus regulate the aeroelastic response. Through a high-fidelity fluid-structure interaction algorithm, the active flap is shown to be an effective regulating mechanism for the fluttering response. The importance of deflecting angle and frequency of the flap on the fluttering control is discussed, and the connection between dominant flow features and dynamic responses of the foil is drawn. Furthermore, a novel stability analysis is proposed to form a reduced-order representation of the problem and its proficiency in capturing different physical phenomena of the system is demonstrated.