Investigation of the Flow Over NACA 63-415 Airfoil

In this article, a two-dimensional, incompressible flow around a NACA 63-415 airfoil, which is widely used as one of the commercial wind turbine blade profiles, is investigated. The goal of this research is to obtain the optimum angle of attack for this particular type of airfoil within a precise range. The Reynolds-Averaged Navier-Stokes (RANS) technique of Computational Fluid Dynamics (CFD) has been employed to examine the flow where the Reynolds number is in the range of 105 to 3x106 and also for the angles of attack from 0° to 20°. These are the typical flow conditions mostly encountered in the real applications of wind turbine blades. The turbulent flow is modelled by means of the Spalart-Allmaras turbulence model since its capability of simulating aerodynamic flows. The ratio of the lift force to the drag force acting on the airfoil has been chosen as a control parameter since the lift force increases the power generated by the turbine, whereas the drag force negatively affects the performance. The present numerical result shows that the maximum lift to drag ratio is observed between 2.5° and 3.5°, depending on the Reynolds number.