Vortex Dynamic Investigation of Wing Slotted Gap of Saab Jas Gripen C-Like Fighter

Canard fighters generally configured with wing canard-deltas and would generate an airflow phenomenon producing vortex cores and lifts. The lift distribution would stall at a high angle of attack (AoA). This study investigated the vortex dynamic of wing canard delta configurations of the Saab JAS Gripen C-like model which create different wing planform than other fighters. The slotted leading edge of the Gripen would develop a strong vortex core on the outer wing, on the same direction with the spin of wing vortex; the outer core would drag the inner vortex core and strengthened. Consequently, the vortex core streamlined in a leading edge of the wing would begin to detach, resulting rolled-up vortices in the wing leading edge followed by a solid laminar stream which tends to curl out. The trailing edge of the wing tended to laminarize backward. The result would be a negative surface pressure on the leading edge above the canard and on the wing which causes more negative surface pressures. An increase in AoA will generate a closer vortex breakdown location to the wing leading edge. The location was calculated as the ratio of the axial velocity value to free velocity (U/U∞) at a value of 0.1. As the AoA increased, the vortex breakdown location moved forwards, upwards, and moved away from the fuselage.