Comparison of Aerodynamic Behaviour between NACA 0018 and NACA 0012 Airfoils at Low Reynolds Number Through CFD Analysis

Abstract

For better designing of an airfoil, the aerodynamic characteristics of the airfoil need to be investigated both experimentally and numerically. Coefficient of lift (C_L), coefficient of drag (C_D), variation of C_L/C_D ratio with angle of attack is very important parameters in CFD analysis. In this study the above parameters are investigated for two symmetric airfoils (NACA0018 and NACA0012) at two different low Reynolds numbers of 300,000 and 700,000. This numerical results show that the stall angle for NACA0018 airfoil at Re=300,000 is less than 17 degree and at Re=700,000 for the same airfoil it is 17.5 degree and this happened due to the increased velocity. C_L increases more linearly than C_D up to about 10 degree so that C_L/C_D ratio increases with the angle of attack and then decreases after or near about 10 degree. It has been also found that higher the Reynolds number, greater the value of C_L/C_D ratio. Besides, it is evident from this simulation that NACA 0012 produces more lift than NACA 0018 for the same Reynolds number. That’s why, NACA 0012 airfoil may be verily used for aircraft application whereas NACA 0018 airfoil may be used in VAWT (Vertical Axis Wind Turbine) And HAWT (Horizontal Axis Wind Turbine) to capture the wind energy and convert it to useable energy which is one form of renewable energy