Aerodynamic performance analysis of NACA 0018 airfoil at low Reynolds numbers in a low-turbulence wind tunnel

The objective of this study was to measure the aerodynamic characteristics of the NACA 0018 airfoil across a range of low Reynolds numbers, with a particular focus on the unique behaviours observed in this regime. The experiments were conducted primarily in a low-turbulence wind tunnel using wall pressure taps, a pressure rake, and a force gauge. The Reynolds numbers investigated ranged from 30.000 to 160.000, with angles of attack spanning from-190 to +20 degrees. A major achievement of this research was the successful acquisition of data at Re = 30.000, where the lift behaviour significantly deviated from that observed at higher Reynolds numbers. The results demonstrated a strong dependency of aerodynamic characteristics on Reynolds number, with the drag coefficient at zero angle of attack decreasing by over 700 percent when Re increased from 30.000 to 160.000. Additionally, two independent techniques for measuring lift force were employed, both yielding consistent results despite the low Reynolds number. The experimental results were also compared with XFOIL and 2-D CFD simulations, which, although not perfectly accurate, provided reasonably good predictions.