Experimental and numerical investigation of the incompressible unsteady viscous flow past the oscillating airfoil

Abstract

This project aims in understanding the basic concept and the flow behavior of the dynamic stall both experimentally and computationally. A fundamental understanding of dynamic stall is important in rotary as well as the fixed wing configurations. A thorough understanding of the dynamic stall process is essential before utilizing the potential of these energetic flows. The incompressible unsteady viscous flow past the NACA 0012 airfoil at the Reynolds number of the order of 105 is simulated and the effects of several parameters are investigated experimentally and computationally. Wind tunnel experiments are conducted at the low speed wind tunnel laboratory, IIT Kanpur. A scotch yoke mechanism is employed to execute the oscillating motion in the airfoil. The sinusoidal motion of the airfoil is given by ( ) ( ). The experiments are conducted at a set of mean and amplitude angle of attack that covered the angle of incidence from -5° to 25°. The study is carried out at Reynolds numbers of 1.15 X 105, 1.7 X 105 and 2.12 X 105 and the reduced frequency of 0.1, 0.15 and 0.2. The experiments are carried out by the surface pressure measurements. Experiments are accomplished to investigate the aerodynamic characteristics of the flow associated with the sinusoidal pitching motion of the airfoil using the technique of surface pressure measurements, force measurements and Particle Image Velocimetry. The PIV technique provides two dimensional vorticity fields in the mid span of the airfoil at the various instants of time. The prominent features of the leading edge vortices, dynamic stall vortices, trailing edge vortices and other secondary flows are captured in the 2D PIV images newline