TY - GEN
T1 - Aerodynamic Impact of Zigzag Tape on the NACA 0018 Airfoil: Experimental and Numerical Insights at Low Reynolds Numbers
AU - Rogowski, Krzysztof
AU - Strachowski, Mateusz
AU - Śledziewski, Maciej
AU - Kubacki, Sławomir
AU - Mikkelsen, Robert Flemming
PY - 2026
Y1 - 2026
N2 - This study investigates the aerodynamic impact of a zigzag turbulator tape on a NACA 0018 airfoil operating at a low Reynolds number of Re = 1.6 × 105, chosen as a representative sectional Reynolds number corresponding to the operating conditions reported for Darrieus-type vertical-axis wind turbines in the literature. Wind-tunnel measurements conducted in a low-turbulence environment are validated against wind-tunnel measurements using two-dimensional and three-dimensional CFD approaches, as well as XFOIL predictions. The numerical analysis employs the γ–Reθ transition model, complemented by a Scale-Adaptive Simulation (SAS) approach in three dimensions, enabling an improved representation of unsteady separation and transitional flow phenomena. The results demonstrate that the inclusion of SAS significantly enhances the prediction of lift, drag, and surface pressure distributions compared to conventional two-dimensional URANS simulations. The presence of the zigzag tape locally modifies the near-wall flow, promotes earlier boundary-layer transition, and effectively suppresses laminar separation bubbles without causing a significant degradation of lift at the highest angles of attack considered. Further more, it is shown—based on two-dimensional simulations performed using different domain topologies—that the predicted aerodynamic characteristics are insensitive to the computational domain geometry, provided that blockage effects remain negligible. The experimental data combined with advanced numerical modelling highlights the importance of scale-resolving approaches for the accurate assessment of passive flow-control devices on thick airfoils at low Reynolds numbers.
AB - This study investigates the aerodynamic impact of a zigzag turbulator tape on a NACA 0018 airfoil operating at a low Reynolds number of Re = 1.6 × 105, chosen as a representative sectional Reynolds number corresponding to the operating conditions reported for Darrieus-type vertical-axis wind turbines in the literature. Wind-tunnel measurements conducted in a low-turbulence environment are validated against wind-tunnel measurements using two-dimensional and three-dimensional CFD approaches, as well as XFOIL predictions. The numerical analysis employs the γ–Reθ transition model, complemented by a Scale-Adaptive Simulation (SAS) approach in three dimensions, enabling an improved representation of unsteady separation and transitional flow phenomena. The results demonstrate that the inclusion of SAS significantly enhances the prediction of lift, drag, and surface pressure distributions compared to conventional two-dimensional URANS simulations. The presence of the zigzag tape locally modifies the near-wall flow, promotes earlier boundary-layer transition, and effectively suppresses laminar separation bubbles without causing a significant degradation of lift at the highest angles of attack considered. Further more, it is shown—based on two-dimensional simulations performed using different domain topologies—that the predicted aerodynamic characteristics are insensitive to the computational domain geometry, provided that blockage effects remain negligible. The experimental data combined with advanced numerical modelling highlights the importance of scale-resolving approaches for the accurate assessment of passive flow-control devices on thick airfoils at low Reynolds numbers.
U2 - 10.1088/1742-6596/3224/4/042016
DO - 10.1088/1742-6596/3224/4/042016
M3 - Article in proceedings
T3 - Journal of Physics: Conference Series
BT - Proceedings of The Science of Making Torque from Wind (TORQUE 2026)
PB - IOP Publishing
T2 - 2026 The Science of making Torque from wind
Y2 - 3 June 2026 through 5 June 2026
ER -