Fluids, Aerodynamics, Drag (Aerodynamics), Biomimetics, Bioengineering, Drag
Dolphins have sinusoidal skin ridges, approximately 30Фμm in height and 60μm in period, that are perpendicular to fluid flow and run circumferential to the body. There has been much debate regarding the effect of these ridges in nature; however, previous studies have shown that these ridges induce vortices in the cavities and provide a slip condition at the surface, demonstrating a potential for drag reduction. This study investigates the effects of a sinusoidal pattern on the lift, drag, and surface air pressure over an airfoil. For this research, static tests at angles of incidence between 0 and 20 degrees were conducted on smooth and patterned NACA 4412 airfoils at a Reynolds number of approximately 100,000. The patterned airfoil demonstrated a more negative leading edge pressure and less variability in the data at the stall angle, indicating delayed separation, but exhibited less lift and greater drag. Above the stall angle, the patterned airfoil exhibited equal lift and less drag. These results imply that the patterned surface delayed the onset of flow separation and has the potential to generate larger amounts of lift.
Gamble, Lawren Lenore, "Detecting flow separation over a bio-inspired patterned surface using a pressure sensor array" (2014). Theses, Dissertations, and Projects. 46.