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

摘要

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 1.8 x 10 exp 6, 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 deg. ^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 constant-vorticity 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 the ground. ^(Author)