Experimental Analysis of a Flapping Aeroelastic Wing and Derivation of Genaralized Curves

There are many potentially attractive applications for flapping Micro air vehicles (FMAV). FMAV have much better performance in low speeds and Reynolds numbers compared to that of fixed wings or MAV. In line with their special advantages of small size، low velocity، high agility and maneuverability، micro or small ornithopters are being potentially considered for applications in rescue missions، remote sensing and spy and reconnaissance operations in small/closed environment. Experimental studies of flapping phenomena are of great importance due to some fundamental challenges faced with theoretical modeling of FMAV. These include complexity in simultaneous modeling of lift and propulsive mechanism، lack of accurate flight dynamic models and a high degree of coupling and nonlinearity of the FMAV dynamic modes. In this research، an elastic flapping wing has been experimentally investigated. The FMAV as well as an instrumented test stand for online measurements of forces، flapping angle and power consumption have been designed and built specifically for this investigation. Moreover، various types of wings having different torsional stiffness، mass and size have been manufactured in order to study the effects of changing both kinematic parameters and mechanical properties of wing، on produced forces and also consumed power. The test results have been achieved for a variety of aerodynamic and mechanical characteristics. A set of new generalized curves have been introduced via dimensional analysis، in which essential parameters of wing such as stiffness، mass، area، frequency and velocity، are grouped together. A new optimization scheme has been introduced based on these general curves، addressing best wing for maximum propulsive efficiency. Flapping performance is shown to be a function of two independent parameters، namely the reduced frequency and the Aeroelastic coefficient. The trends and the generalized curves can be widely utilized in the design of FMAV or other elastic lift-propulsion generating structures.