Improvement of Energy Extraction Efficiency for Flapping Airfoils by Using Oscillating Gurney Flaps

The present paper proposes an oscillating Gurney flap to enhance the power extraction efficiency of a flapping airfoil system. Two-dimensional Navier–Stokes resolutions by the flow solver fluent are performed. To alter the flap position during the flapping cycle, a dynamic mesh technique is used. The flow regime is considered fully laminar, with a free stream Reynolds number of Re = 1100. Results show that, the synchronization of the Gurney flap motion with the central flapping airfoil motion generates a virtual camber which corrects the pressure distribution and ultimately enhances the lift force during both, the up-stroke and down-stroke stages. The lift enhancement is interpreted to an improvement in the output power as compared to a clean flapping extractor.