Date of Award
Master of Science (MS)
The focus of this thesis is to evaluate the aerodynamic performance of NREL S809 airfoil (widely used airfoil for wind turbine blades) with a trailing-edge flap by numerical simulations. In the simulations, the geometry of the flap and the gap between the main element and the flap are varied. The airfoil geometry is created in Design Modeler and structured mesh around the airfoil is generated using meshing software ICEM. Simulations are performed using the Reynolds-Averaged Navier-Stokes (RANS) equations with SST k-ω, Spalart-Allmaras (SA) and Wray-Agarwal (WA) turbulence models at Reynolds number 106 at angles of attack of 0, 5o, 10o, 15o, and 20o. First, numerical solutions are validated against the experimental data for S809 airfoil without flap. Then the numerical simulations are conducted with a triangular Gurney flap at various angles of attack. The lift coefficient and the drag coefficient are calculated and are compared with S809 airfoil without flap to evaluate the effect of flap on the airfoil performance. The pressure contours, turbulent kinetic energy contours, and streamlines are plotted and compared for airfoil without and with flap to analyze the details of the flow field. Computed results show that the presence of trailing-edge flap provides higher lift and lift-to-drag ratio compared to original airfoil demonstrating its promise for larger wind energy extraction.
David Peters Swami Karunamoorthy