Abstract: An improved unsteady vortex lattice method (UVLM) is proposed in this article to simulate the surrounding flow of a flapping-wing micro aerial vehicle (Flapping-wing MAV) precisely which takes into full account the features of the flexible flapping-wing model. The influence of instantaneous wing shape velocity on the aerodynamic forces, the induced drag and the wake stretching as well as dissipation are modeled in this method. And a visual program based on this method is developed. The results are 20% more accurate in lifting coefficient calculation and 70% more accurate in thrust coefficient calculation, which are verified by the computational and experimental data. To further improve the performance of the UVLM, the influence of wake vortex ignoring on time savings and precision is studied. The results show that the savings in central processing unit (CPU) time with wake vortex ignoring could be up to 2/3, which indicates the important value of UVLM in the optimization of flapping-wing vehicle design as a fast aerodynamic approximation method.

Key words: flexible flapping-wing, aerodynamics, unsteady vortex lattice method, wake vortex ignoring, implementation