Investigation of Flow Field in Deep Dynamic Stall over an Oscillating NACA 0012 Airfoil

This paper presents the investigation on the phenomenon of a deep dynamic stall at the Reynolds number of the order of 10(5) over an oscillating NACA 0012 model. Wind tunnel experiments are conducted to investigate the aerodynamic characteristics of the upstroke and downstroke phase associated with the sinusoidal pitching motion of the airfoil using the technique of surface pressure measurements and Particle Image Velocimetry. The validation of the lift curve slope of upstroke and downstroke with the Prandtl's thin airfoil theory reveals the fact of massive flow separation during the deep dynamic stall regime. Numerical simulations are performed using Reynolds averaged Navier Stokes turbulence models such as RNG K-epsilon and SST models. The data obtained from these models have been compared with the experimental data to investigate the aerodynamic features of the deep dynamic stall regime. The comparison shows that the URANS with K-epsilon model is in good agreement with the experimental data within the reasonable regime.