Effect of Vortex Impingement on the Aerodynamic Performance of a NACA 0010 Airfoil*

This study examines the impact of vortex impingement on the aerodynamic performance of a NACA 0010 airfoil. The experimental setup involves vortex rings generated by a pulsed jet from a 2-inch nozzle at a nozzle exit Mach number of 0.1. These vortex rings impinge on the airfoil located three nozzle exit diameters downstream. The pulsation frequency, quantified using the non-dimensional Strouhal number (St), was varied from 0.06 to 0.2 to explore the full range of realistic conditions. The Reynolds numbers based on the nozzle exit diameter and the pulsed jet average exit velocity is 103,000. The measurements involve both force and flow field measurements using Particle Image Velocimetry (PIV). The results demonstrate significant and non-trivial variations in the lift coefficient at different Strouhal numbers. At St = 0.06, the lift coefficient was measured to be approximately 0.3, which increased to 0.6 at St = 0.2. These findings indicate that the airfoil's lift generation capabilities are highly influenced by the frequency of the impinging vortex. The drag coefficient also exhibits pronounced fluctuations due to vortex impingement. At St = 0.06, the drag coefficient was found to be approximately 0.04, which increased to 0.2 at St = 0.2. These results highlight the impact of vortex impingement on the airfoil's aerodynamic characteristics, leading to substantial changes in lift and drag forces. The obtained insights provide valuable guidance for designing airfoils in engineering applications such as wind turbine blades and aircraft wings, where maximizing lift and minimizing drag are essential for efficiency and performance.