An Overview of Progress in Flapping Wing Power Generation

Recently, with the increase in power generation and consumption needs of our planet, the global community has been concerned by two major issues: the severe environmental impact of burning fossil fuels and the availability of finite resources of fossil fuel for conventional power generation. These two factors are the main reason behind the search of alternative methods to harvest energy from alternate renewable sources. One such alternate method is the use of bio-inspired unsteady flapping wing power generation which has gained much interest from engineering community. At low Reynolds number, natural flyers and swimmers such as birds, insects and fish employ the unsteady vortices to generate thrust and lift which makes them one the most agile and efficient flyers and swimmers. Better understanding of the aerodynamic forces generation mechanisms associated with the flow over flapping wings can help us develop efficient micro and nano aerial vehicles (MAVs/NAVs) and with the proper phasing between different modes of wing motion, flapping wings can also be employed for the power extraction from low speed river or ocean tidal streams. It has been shown that flapping wing power generators can harness power with comparable efficiencies to that of conventional rotary wind turbines. The aerodynamics forces generation by flapping wings is a complex phenomenon and depends on many parameters like the mode of motion, phase difference between different modes, amplitude of flapping, wing shape and wing flexibility etc. Lately, there has been concerted effort to find the optimal conditions to generate maximum thrust and lift using flapping wings. In this paper, a brief overview of fundamentals of flapping wing aerodynamics and recent advancements in the research and development of the flapping.