Numerical Simulation of the Airfoil Flowfields at Angles of Attack from 0° and 180°

Vertical axis wind generators had received wide attention for its excellent aerodynamics characteristic and other advantages. In order to study the force exerted on airfoil when it rotated a full circle, it was necessary to simulate the flowfields of airfoil within the whole range of angles of attack. In this paper, different turbulence models and C type grid were firstly employed to simulate the flow field of NACA0012 airfoil when Ma was 0.15, Re was 0.5×10⁶ and the angles of attack were 10° and 70°. The results were compared with experimental data to determine the most suitable turbulence model. Then with the chosen turbulence model, flowfields of airfoil at angles of attack from 0° and 180° were simulated using three grid types. The results indicated that the results of S-A turbulence model had the best agreement with the experimental data; The boundary layer was full attached for angle of attack of 10°, while large-scale separation and vortex shedding occurred for 70°; The predicted lift coefficient, drag coefficient and driving force of C type grid agreed well with the experimental results; The net driving force would cause airfoil to rotate in the direction of the leading edge of the airfoil and it could be used to optimize airfoils.