NACA 5312 in ground effect - Wind tunnel and panel code studies

Abstract

Wind tunnel pressure measurements were made on a NACA 5312 airfoil at various distances from the ground and at various incidences. Tests were carried out at a freestream Reynolds number of l.SxlO, resulting in turbulent flow over most of the airfoil. The nondimensionalized trailing edge distance ranged from 0.0 to 0.5, while the incidence ranged from -4 to 16 degrees. The presence of the ground was simulated via the image method, i.e., by using a pair of symmetrically opposed airfoils that formed a symmetry plane midway between them. A numerical method based on constantvorticity flat panels was used to assess the usefulness of panel methods in studying airfoils in ground effect. Results from the panel code were compared to the experimental pressure distributions. While the experimental results were considered reliable, panel methods were not deemed effective in predicting pressure distributions and aerodynamic coefficients for airfoils operating at various incidences and various ground distances. Computational methods must model the presence of boundary layers on the airfoil and on