Effects of thickness and camber ratio on flow characteristics over airfoils

Abstract

This study ensures experimental and numerical investigation of different airfoils to observe and understand how camber ratio affects the flow characteristics over surface of different airfoils. Experimental results in the previous studies were used while the numerical study was performed for present investigation. Reynolds numbers based on the airfoil chords were 1x105 and the angle of attack of 8°. Instantaneous voltage output data were used in order to detect transition location for NACA 4412, oil surface visualization experiments were presented for NACA 2415. In the numerical analysis, values of u/U∞ and turbulent kinetic energy were presented for NACA 4415 airfoil. The experimental results denoted that the change of camber ratio and thickness significantly affected the flow phenomenon such as boundary layer separation or formation and progress of the laminar separation bubble. The long bubble was clearly observed with accumulation of pigments at oil-flow measurement experiment. By increasing the camber ratio with the use of NACA 4412 airfoil, the long bubble turned into the short bubble. Briefly, not only the progress and formation of laminar separation bubble was being affected, but also the onset of transition point was obviously influenced by changing of camber ratio.