Numerical and Experimental Investigation of Thickness Effect on the Cambered Airfoils at Low Reynolds Numbers

Abstract

In this study, experimentaland numerical study for the cambered airfoils was conducted at Re = 1.5x105and Re = 2.5x105and different angles of attack. In the experimental analysis, oil-flow visualization and force measurement techniques were utilized. For numerical analysis, the k-w SSTtransition model was used to predict the flow over the cambered airfoils. The time-dependent aerodynamic force coefficients of the cambered NACA2412, NACA2415 and NACA2418 airfoils pointed out the force fluctuations formations due to unsteady flow on the airfoils. Whereas the force coefficient increased as the airfoil thickness increased, a decrease in the lift coefficient was observed due to adverse pressure gradients. Moreover, as the airfoil thickness increased, the separation occurred earlier due to the effect of adverse pressure gradients, so it got closer to the leading edge and became shorter. However, the prediction of the separation point was delayed in numerical analysis and the prediction of the reattachment points was more consistent.

Keywords

• airfoil
• lift coefficient
• transition model
• oil-flow visualization