Effect of backward facing step on the aerodynamic characteristics of NACA 0015 airfoil

Abstract

The purpose of this research is to study the lift and drag characteristics of a NACA 0015 airfoil with a backward facing step. A backward facing step on the upper surface has the potential to improve the aerodynamic characteristics by reducing the drag coefficients and increasing the lift-to-drag ratios considerably. For a free stream velocity, the point of separation is determined by CFD analysis with increasing the angle of attack. A backward facing step is introduced just prior to the point of separation. The goal of improving the aerodynamic performance of the airfoil is inserted by searching the best configuration through gradually increasing the depth of facing step. A wind tunnel test on a NACA 0015 has been also conducted to verify the results from CFD analysis. The results show that reduction in drag is possible by separation delay with introducing the step. Though the reduction in lift has been observed, the lift to drag ratio also increases which is an important parameter in aerodynamic characteristics.