It is clear from Fig. 2-3 that the incoming flow transforms into a vortex core after contact with the wing. This vortex core is infact the origin of a complex three dimensional flow pattern. This is the “horseshoe vortex”. The vortex core was formed at about 86 mm away from the wing leading edge and at a height of around 13 mm from the floor. The presence of this vortex as it wraps around the wing was not studied by Barberis et al. 3 in this experiment. This phenomenon is however, a significant structure and has greater effects in producing lift loss and drag on the wing.
The same experimental setup as shown in Fig. 2-2 was also used to study the behavior of localized seuction. In this regard, a slot with dimensions of 100 x 80 mm2 was used for applying suction. This slot was placed at two different locations. In the first case for Slot1, slot position was chose in such a way that it overlapped the saddle point location observed for the no suction case. Whereas, in the second case of Slot2, the location was chosen between the saddle point and the wing starting point.
Fig. 2-4 Top View of the Experimental Set up with Suction 3
Various suction rates between suction coefficients (Cq) of 0.09 to 1.0 were applied through the suction holes to study the effects of suction in the wing plane of symmetry ahead of the wing leading edge at 0o incidences. It was observed that suction application had a significant consequence on the flow detachment characteristics in the wing symmetry plane. These effects are shown in Fig. 2-5.