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This research describes the investigation of the behavior of the flow over a 2D Flapping airfoil for flapping wing of Micro Aerial Vehicles (FWMAV) at very low Reynolds number regieme. The behavior of the flow wake at the trailing edge is studied by the analysis of streamlines for each incidence angle and results are compared by the study of two different flapping airfoils at two different fluids. The use of Fluid Structure Interaction (FSI) simulation has shown accuracy in predicting lift and drag forces at different angles of attack for upstroke and down stroke. This work simulates a classical flow pattern (Von Karman Street) that can form as fluid flows past a flapping NACA0012 airfoil, and S1223 airfoil at low Reynolds numbers and low velocities. These two airfoils have been selected and investigated by using basic computational fluid dynamics and fluid structure interaction modules. The S1223 airfoil, designed by University of Illinois at Urbana and the NACA0012 airfoil were selected for their high lift characteristics at low Reynolds number regime. Simulations were also conducted to check the lift and drag forces for both airfoils at low Reynolds number regime. Velocity distributions were analyzed at different angles of attack for these airfoils. The magnitude and the frequencies of the oscillation generated by the fluid around the airfoils were computed and compared between the airfoils.

This research discusses preliminary design of a Flapping Wing Micro Aerial Vehicle (FWMAV). One approach is to develop a biologically-inspired flapping wing MAV that can maneuver into confined areas and possess hover capabilities. This platform can potentially be equipped with microphones, cameras, and gas detectors, but one major challenge is the low Reynolds number aerodynamics. The critical components for successful flight include size, weight, and energy efficiency. Preliminary efforts include mechanical designs for payload, biologically inspired chassis, wing and tail.

This research presents the development of a bioinspired flapping flight system and a characterization of its performance when operating in turbulent airflow conditions. This system consists of a structure installed within wind tunnel for two dimensions and three dimensions of a Flapping Wing Micro Aerial Vehicles (FWMAV). Each airfoil or wing is able to deform into a classical flow pattern is the von Krmn vortex street that can form as fluid flows past an object. These vortices may induce vibrations in the object. This problem involves a fluid structure interaction (FSI) where the large deformation affects the flowpath. The exert load is predominately performed in the trailing edge of the airfoil or on the tip of the wing, and the reaction forces are generated by the feathers located at the leading edge. For this study, the focus presents a benchmark case of the NACA0012 and s1223 airfoils with the trailing edge flap design operating in a turbulent airflow. Finite element analysis (FEA) is used to model the flow field and the fluid-structure interactions using Direct Numerical Simulation. Additionally, the airfoils or wings' aerodynamic performance is comparatively analyzed between time-dependent and FSI turbulence model. This paper discusses how these two air foils or wings, and time-dependent FSI turbulent flow simulation results can be developed to serve the flapping flight for unmanned aerial system.

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