AERODYNAMIC ANALYSIS OF FLAPPING WING MICRO AIR VEHICLES

Abstract

Micro air vehicle (MAV) is defined as unmanned air vehicles with wing to wing span of 15 cm and weight not more than 100 grams, specifications defined by American Defense Advanced Research Projects Agency (DARPA). MAV finds its applications in surveillance, rescues and other strategic military purposes. The design of a Micro air vehicle (MAV) is an emerging new area of current research. Especially, the problem of aerodynamic behavior of the flapping wing of an mav is a very challenging problem for researchers. It is particularly helpful for design and development of Micro Air Vehicles where optimized lift and thrust generation is very much required. In the present research, the impact of airfoil shapes on the flapping performance has been investigated by comparing the lift and drag coefficients by using three different airfoils which include flat plate, ellipse and NACA0014 of same thickness in pure plunging motion. Computations were carried out at various Reynolds number that cover entire spectrum from fully laminar to fully turbulent flow regime and at various reduced frequencies in order to explore behavior of different shapes of airfoils and their correlation with Reynolds number and reduced frequencies. Unsteady incompressible Navier Stokes equations in this study were solved assuming flow to be laminar at low Reynolds number whereas for high Reynolds S-A turbulence model has been used to carry out computations. O-type grid has been used to descretize the computational domain. Results obtained show that the airfoil shape has strong influence on flapping performance and its correlation with the Reynolds number and reduced frequency has also been found which leads to the conclusion that at high Reynolds number and for higher reduced frequencies, shaped airfoils that is NAC0014 produces best thrust.