Wake Shedding Characteristics of an Airfoil in Low Reynolds Number Regime
摘要
This study investigates the wake characteristics of the low-speed E214 airfoil within a Reynolds number (Re) range relevant to micro air vehicles and small-scale wind turbine applications. The experiments are conducted in an open channel wind tunnel and tested for Re range of 3 × 104–7 × 104. The effects of probe location, Re, and angle of attack (AoA) on wake behavior are examined. Results reveal that a single dominant frequency is observed at streamwise probe locations close up to x/c = 2.0, indicating a stable wake structure near the trailing edge region. Beyond this point, multiple frequencies emerge, signifying increased vortex complexity and interactions. The amplitude of the dominant frequency decreases as the probe moves downstream, reflecting energy dissipation. The shedding frequency increases with Re at a fixed AoA, whereas it decreases with an increase of AoA at a constant Re. The Strouhal number analysis shows it remains nearly constant with increasing Re for a given AoA due to the proportional relationship between shedding frequency and freestream velocity. However, the Strouhal number decreases with increasing AoA at a fixed Re, attributed to enhanced flow separation and larger, slower-moving vortices.