Fluid-Structure Interactions in Flexible Airfoils: A Combined Approach Using DIC and PIV Techniques

Fluid-structure interaction response of a highly flexible high aspect ratio airfoil was investigated through a series of water tunnel experiments, employing a cutting-edge measurement technique that combines digital image correlation (DIC) and particle image velocimetry (PIV). Throughout the measurement process, we concurrently captured both flow and structure tracers through high-speed imaging, which were subsequently integrated to provide synchronized flow field and dynamic structural response data. Our primary focus was on studying flow-induced vibration response in flexible airfoils under diverse operational conditions. This included investigating angles of attack spanning from 0° to 20° and exploring a broad range of flow velocities. Our findings revealed a dynamic response that exhibited limit cycle oscillation patterns, with different modes of vibration, including bending, torsional, and edgewise modes, depending on the operational conditions, such as changes in angle of attack or flow velocity. Additionally, at higher angles of attack and flow velocities, the airfoil demonstrated multifrequency oscillations, involving various modes contributing to its overall response.