Role of partially bumpy surface to control the flow separation of an airfoil

The aim of the research is to control the flow separation of an airfoil by providing a partial bumpy on the upper surface. In order to obtain the highest levels of performance efficiencies for mission varying aircraft, it is necessary to either: (a) alter the boundary layer behavior over the airfoil surface-flow control methods of interest here, and/or (b) change the geometry of the air- foil real time for changing free stream conditions-adaptive wing technology. Geometry of the airfoil can be changed by providing bumpy on the upper surface. To investigate the effect of introducing large scale surface roughness through static curvature modifications on the low speed flow over an airfoil, two types model are prepared. One is regular surface model another is bumpy surface model. All the models are prepared by wood and the experiments are conducted using 36×36×100 cm subsonic wind tunnel. From the experimental investigations it has been observed that the flow separation on the airfoil can be delayed by using the bumpy on the upper surface. Flow separation occurs at 8° angle of attack in the smooth surface. But in bumpy surface it occurs at 14° angle of attack. That indicates the bumpy surface successfully controls the flow separation and increases the lift force of an airfoil.