DescriptionUnsteady flows are very common in nature. Birds, insects, fish and other animals predominantly rely on unsteady phenomena for locomotion. In the past century the primary focus of aerodynamicists was on steady flows. Currently, there is a renewed interest in unsteady flows due to their applications in MAV’s and energy extraction. The purpose of this thesis is to investigate unsteady flows with a traditional N-S solver and a new Vortex solver based on the Discreet Vortex Method(DVM). We found that the vortex method is very suitable to simulate flapping flight, especially for parametric studies before proceeding to a full fledged N-S solver. Our results show that the Vortex method is an order of magnitude faster than a N–S solver.