The Applicability of Unsteady Vortex Panel Methods to the Design of Hovering Flapping-Wing Micro Air Vehicles

An unsteady 2D vortex panel code is developed based on potential flow methods. The code is written in MATLAB and allows for arbitrary motion of an airfoil through a stationary, inviscid fluid. The surface of the airfoil is represented by a series of vortex panels, each having a linear distribution of circulation across its length; the wake is represented by discrete vortices shed from the trailing edge which move with the local velocity field. The panel code is validated against a similar code being used by researchers at the Naval Postgraduate School with excellent agreement. The code is then used to simulate an airfoil undergoing flapping oscillations in hovering mode and to evaluate the forces generated. The results are compared with results from FLUENT, a commercially available CFD code, in order to assess the applicability of vortex panel methods to the design of hovering flapping-wing Micro Air Vehicles. The results of the study show that the panel code compares fairly well with CFD predictions, though it is unable to capture viscous effects such as leading-edge vortices. If the code is extended to three dimensions and the leading-edge vortex can be modeled, vortex panel codes could prove very beneficial to designers of flapping-wing MAVs.