Computation of transitional flows around an airfoil with a movable flap

Flow characteristics around an airfoil at Reynolds number from 10⁴ to 10⁵ are of substantial interest to many applications, such as micro air vehicle, biological flight and flsh swimming. In this study the effect of a movable flap on the flow structure in this regime is investigated using a moving grid technique. In addition to the Reynolds number, the flapping frequency plays a major role in determining the separation and re-attachment points, pressure distribution, and vortex dynamics. Laminar, transitional, and turbulent flow computations have been conducted with turbulence and transition issues assessed in the context of the κ - ε and eⁿ method, respectively. Experimental information such as the pressure distribution on the airfoil interface is collected to investigate the effect of the flap movement on the velocity and pressure fields, including the recirculation size a location.