Study on the Vortex Wake of an Airfoil Equipped With Flexible Trailing Edge Fringe

With the inspiration of owl’s silent flight, a traditional airfoil S833 equipped with flexible fringe as an extension to the trailing edge is investigated through the experimental study in a wind tunnel and the numerical simulation. The newly constructed airfoil is modeled, manufactured and investigated. In the experimental study, a high-resolution Particle Image Velocimetry (PIV) system is employed to make detailed flow field measurements to quantify the generation and the shedding of the trailing edge vortices at various AOAs. In the numerical simulation, an incompressible, 2D and viscous flow solver in the CFD software FLUENT is utilized to conduct the numerical simulation on the vortex feature in the wake of the airfoil. Both experimental results and numerical results reveal that the existence of trailing edge fringe can reduce the strength of the shedding vortex, create more vortices with smaller gap in between and smaller size in scale at AOA=9 degree. It is also found in the experimental study that the existence of flexible trailing edge fringe can help break the large-scale swirls into small-scale weak swirls for relatively large angle of attack, while the motion of the fringe might induce additional Reynolds stress at lower angle of attack.