NUMERICAL INVESTIGATIONS OF THE EFFECTS OF DIFFERENT LEADINGEDGE PROFILES ON THE VORTEX FLOWS OVER DOUBLE-DELTA WINGS

The effects of different leading edge profiles on the vortex flows over double delta wings were investigated both numerically and theoretically. And the different mechanisms of the leading edge profiles affecting the vortex flows over both single delta wings and double delta wings were analyzed and contrasted. While over single delta wings, the structures of the vortices resulting from sharp leading edges are organized best, over double delta wings, the structures of the vortices resulting from round leading edges are closer to the wing surface, and are tighter than those resulting from sharp leading edges. This shows that, over double delta wings, round leading edges have stronger inducement abilities, and can constitute more favorable vortices interactions, which makes it easier to transfer vorticity from the inner vortices to the outer vortices through the shear layers. Thus, the combined vortices become more stable, and the vortices breakdown can be well prolonged. Moreover, because they are closer to the wing surface, the vortices resulting from round leading edges can provide a higher nonlinear lift than under other circumstances, which is different from the traditional views.