Aerodynamic Analysis of the NACA 4412 Airfoil
Abstract:
Multiple pressure readings were measured on the surface of an infinite wing (span equal to tunnel width) NACA 4412 airfoil, as well as pressure in the wake of the airfoil. These tests were done at a Reynolds number of 2e5 as well as 3e5. The pressure values were used to calculate the lift, drag, and moment forces on the airfoil, as well as to find the stall angle. It was found that a higher Reynolds number yields a higher stall angle, 1 degree in this case. The data acquired was compared to historical data, simulation, and a second testing method for validation. It was found that the pressure readings across the surface of the airfoil very closely mimicked those found through simulation (XFOIL). Similarly, plotting coefficient of lift vs alpha yielded a plot that very much resembled historical data as well as simulation. Drag, however, was found to be extremely difficult to capture utilizing the pressure ports over the wing itself. Instead, better results were obtained through the use of the pressure rake, which captured the lost energy of the flow. Further analysis was done with the use of a Force Balance device, which output force and moment values for all three axes. Two airfoils were used for this analysis, with the only difference being aspect ratio. Reynolds number was matched at 3e5 for theses tests. It was found that the lower aspect ratio wing stalled at a higher angle of attack, but also yielded a smaller Lift/Drag ratio for all angles other than stall.