A Study Of Low-Reynolds-Number Performance Over A Two-Dimensional Airfoil For Micro-Air Vehilce

Recently interest in the development of micro-air vehicles (MAVs) has led to an interest of the aerodynamic performances of airfoils at low Reynolds numbers. This paper discusses the characteristics based on four types of airfoils which are, respectively, symmetrical Joukowsky, cambered Joukowsky, elliptical and NACA0012 airfoils. The flow over the airfoils is considered to be two-dimensional incompressible flow at low Reynolds numbers and the potential-flow theory and the solutions of the boundary layer are carried out. Meanwhile, an experimental study was performed to investigated the characteristics of the symmetrical airfoil in the low turbulent tunnel.The numerical model of an airfoil can be given by Joukowski transformation and conformal mapping. Through a series of computations, potential velocity distributions of foil surfaces are solved. The properties of the shear layers are analyzed in the states of purely laminar, fully turbulent and laminar+transition+turbulent using the Thwaites Integral and Head Integral methods.The test was conducted in the low turbulence wind tunnel in the Northwest Polytechnical University. Static pressures and velocity distributions over the foil surfaces can be obtained through processing the test data. The characteristics of the shear layers are investigated again with the velocity distributions which are come from the test and compared with the results of theoretic analysis. The purpose of the comparison between computational and experimental results is aimed at some suggestions on the shapes of airfoils at low Reynolds number.