Effects of wing-tip vortices on lift of the flat plates with low aspect ratio

This paper describes the flow around flat plates with different aspect ratios using the method of flow visualization by hydrogen bubbles. The flow around plates was visualized over the central section and the lower tip of the plates in a circulating water tank. At an attack angle smaller than the stall, the flow on the suction side of the central section separated at the leading edge, and then reattaching at the rear part of the plates. This phenomenon disappeared at angles larger than the stall. A series of spiral wing tip vortices was formed at the lower tip of the plates, which weakened at an angle larger than the stall. The maximum lift coefficient measured by this experiment was greater than that of the linear lift derived from the potential theory. The difference was greater at lower aspect ratios. This means that the lower the aspect ratio, the higher the effects of the wing tip vortex on the lift of flat plates.