Abstract
In teaching fluid mechanics, we have been making researches of high lift devices of an airplane, flap and slat by using a smoke wind tunnel. In this experimental study, we used NACA4412 wing section, and searched the optimum shape of a slot between the main wing and the flap. By the partial flow visualization technique, we confirmed the slot shape that a smoke streak-line passing through the slot was attached to the upper surface of the flap and by the force measurement technique, we also confirmed that the slot shape mentioned above had brought maximum lift coefficient. In this paper, we refer to the partial flow visualization of slotted flap of 40% chord length.
