Date of Award

Spring 5-15-2020

Author's School

McKelvey School of Engineering

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Master of Science (MS)

Degree Type



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 0o, 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 Gurney flap at various angles of attack. The lift coefficient and the drag coefficient are calculated and are compared with S809 plain flap to and Gurney flap to evaluate the effect of flap on the airfoil performance. The velocity and pressure contours are plotted and compared for airfoil within three turbulence models on two different types of flaps to analyze the details of the flow field and pressure distribution. Computed results show that the presence of trailing-edge Gurney flap provides higher lift and lift-to-drag ratio compared to original airfoil demonstrating its promise for larger wind energy extraction.


English (en)


Ramesh Agarwal

Committee Members

David Peters Swami Karunamoorthy

Included in

Engineering Commons