Experimental investigation of the aerodynamic performance of symmetric and asymmetric aero-shaped vortex generators

In this study, the aerodynamic performance of National Advisory Committee for Aeronautics (NACA) 4415 airfoil equipped with two different aero-shaped vortex generators (AsVGs) was experimentally investigated. The tested VG designs were based on NACA 0015 (symmetric) and SD7080 (asymmetric) profiles and positioned at four chordwise locations (x/c = 0.1, 0.2, 0.3, and 0.4). Force measurement experiments and surface oil flow visualization (SOFV) were conducted in a low-speed wind tunnel at a Reynolds number (Re) of 1.3 × 105 to assess lift (CL), drag (CD), and stall behavior. The results revealed that AsVG placement at x/c = 0.1 yielded the most significant aerodynamic improvements. At this location, the SD7080 AsVG delayed stall by 5° and increased CL/CD by 75.9%, while the NACA 0015 AsVG delayed stall by 4° and improved CL/CD by 44.9%. In all configurations, drag was reduced due to reverse flow structures forming on the inner surfaces of the AsVGs. SOFV analysis showed that AsVGs disrupted long laminar separation bubbles and extended the attached flow region, especially at x/c = 0.1 and 0.2, where attachment persisted up to x/c = 0.9. Conversely, at downstream positions (x/c = 0.4), aerodynamic improvements were minimal due to limited interaction with the boundary layer. These findings demonstrate that appropriately shaped and positioned AsVGs offer significant passive flow control capability, particularly in enhancing stall characteristics and aerodynamic efficiency. Overall, the study provides valuable insight into optimizing vortex generator geometry and placement, which can support the design of more efficient aerodynamic systems in both aviation and wind energy applications.