Comparing unsteady force models for a flapping wing in hover

Adriana Basbous Moukarzel

Master project

Flying insects are capable of generating large lift forces at high angles of attack. They can hover and move at high speeds in virtually any direction. By controlling the kinematics of their flapping wings they demonstrate a high flight manoeuvrability, a feature pursued in micro aerial vehicles (MAV) flight. One of the most important ow structures believed to enhance lift has been identified as the leading edge vortex (LEV). It is the vortex that starts at the leading edge, develops behind the wing during half a stroke and is stabilised by an axis flow, feeding it along the span of the wing. In this work, two theoretical force models were tested using experimental data previously obtained on a scaled flat plate wing (Krishna et al. 2016). The objective of this study is to test the limits of predictability of each model and to identify the contributions to the total lift by the flow structures surrounding the wing. The first model was developed by Greenberg (1947) and the second is based on complex potential ow theory. Experimental data included force measurements using a force sensor attached to the wing and particle image velocimetry (PIV).