Figure 9. Polar curves (𝐶L-𝐶D) for the Baseline airfoil, Static Extended Trailing Edges (SETE), and Gurney Flaps (GF), showing the shift in lift and drag characteristics across various angles of attack, highlighting lift augmentation and drag penalties relative to the baseline

From

Numerical Investigation of a NACA 0012 Airfoil with Static-Extended Trailing Edges and Gurney Flaps for Low-Reynolds-Number Wind Turbine Applications

Tiberius S. Gikenyi, Churchill O. Saoke, Joseph N. Kamau

American Journal of Energy Research. 2025, 13(3), 86-95 doi:10.12691/ajer-13-3-2