Effect of aero-shaped vortex generators on NACA 4415 airfoil

Abstract

A parametric study was carried out to investigate the effect of aero-shaped vortex generators (AsVGs) on NACA 4415 airfoil by comparing conventional vortex generators (CVGs). Force and flow visualization experiments were carried out for the CVGs and AsVGs at Re = 1.4 × 105. Six different configurations were selected for the positioning of the CVGs to investigate the best one. The best configuration was applied to the Aero-shaped VGs type, which is generated with the S1223 airfoil model. The results indicated that even if AsVGs did not show better performance to delay the stall angle when compared with the CVGs, in some positions they produced the same stall performance as the CVGs. Moreover, aero-shaped VGs increased the lift coefficient (CL) more than the conventional ones in the pre-stall region. At x/c = 0.1, CL and CD improve by up to 107.7% and 23.39% compared to baseline, respectively. At α = 18° and Re = 0.8 × 105, AeM5 at x/c = 0.1 increased the CL by 102.45% compared to the baseline model. While the CVGs increased the lift coefficient (CL) and postponed the stall (α) angle up to 4° according to the baseline model, the CVGs also caused an overall increase in the drag coefficient (CD). AsVGs decreased the drag coefficient (CD) more than conventional ones. Lift to drag ratio (L/D) of AsVGs is higher than that of the CVGs. The results of the surface oil flow visualization showed that both CVGs and AsVGs segmented the laminar separation bubble (LSB) and formed attached flow zones on the airfoil surface. As a result, AsVGs can be used as an alternative to CVGs in flow control applications.