Effect of surface roughness on aerodynamic performance of the wing with NACA 4412 airfoil at Reynolds number 1.7 × 105

Abstract

Drag reduction is of paramount importance in an effort to enhance the aerodynamic performance of any aerial vehicle. Wings of avian and fins of aquatic animals which utilize their skin roughness to move faster beating the drag are the main source of conviction. This study conducts an experimental investigation to examine the effect of skin friction on the aerodynamic characteristics of a wing by inducting surface roughness at different chord locations (30% and 45% of the chord) of the wing. As a matter of course, wind tunnel tests were performed by fixing emery paper of two different grits (E480 and E4220) in chord-wise direction over two different chord positions on the upper side of the airfoil. The experiments were carried out on a wing having airfoil NACA 4412 at Reynolds number 1.7 × 105. Results revealed that the different surface roughness at different chord locations provide significant variation in lift and drag characteristics and also stall attributes. Surface roughness on the wing surface is found to play a major role in increasing the drag and delaying the stall separation. During takeoff and landing, the aircraft needs to fly at higher angles of attack in comparison to the cruising condition. The surface roughness can be activated only during the takeoff and landing phases by using a servo mechanism for the future aircraft applications.