Colloquium: Pepijn Slooter (FPT)

Wind turbines are vital for sustainable energy, and understanding deep dynamic stall is key to optimizing their performance. This study explores deep dynamic stall through wind tunnel tests on a NACA643418 airfoil at TU Delft, focusing on 40°, 50°, and 90° angles of attack. Experiments reveal trends in lift and drag coefficients (\(C_l\) and\(C_d \)), identifying laminar separation bubbles and trailing edge separation as main stall modes. Significant aerodynamic performance differences between upstroke and downstroke are noted, especially at angles over 25°. Increased frequency and amplitude reduce shedding frequency's impact at 40° and 50°, but it remains significant at 90°. Hysteresis plots show higher drag and lift coefficients during the downstroke, intensifying with frequency and amplitude. Phase-averaged PIV images confirm flow dynamics' impact, showing less reverse flow during the downstroke. The study concludes that deep stall disrupts airflow, increases drag, and affects lift, with vortex shedding as a key factor.

Supervisor: Jemil Znaien