Application of Proper orthogonal decomposition to study the FSI behavior of a flag in a laminar jet

The flutter in the flag causes large-scale deformations of the flag with a close-coupling between flag structure and fluid flow around the flag. The flutter shape of the flag has an impact on the aerodynamic performance of the flag. This study aims to use Proper Orthogonal Decomposition (POD) to quantify the FSI flow features and their impact on aerodynamic behavior. For this study, the flag was placed at the outlet of a laminar jet facility, and the flag samples were fabricated of a flexible cellulose acetate membrane with known material properties. Particle Image Velocimetry (PIV) is used to measure the velocity flow field around the flag, and a high precision load cell is used to measure the aerodynamics load experienced by the flag.  POD provided a modal description of the flow behavior and allowed to quantify the impact of the flow structures on the aerodynamic performance of the flag. The results showed a unique correlation between the flow structure and aerodynamic load experienced by the flag.