Vortex-Wing Interaction of a Close-Coupled Canard Configuration

The thin-layer Navier-Stokes equations are solved numerically to investigate the effects of canard vertical position on a close-coupled, canard-wing-body configuration at a transonic Mach number of 0.90 and angles of attack ranging from — 2 to 12 deg. Canard-wing interactions are investigated for the canard positioned above, coplanar with, and below the wing (high-, mid- and low-canard positions, respectively). The computational results show favorable canard-wing interactions for the high- and midcanard configurations. The unfavorable lift and drag characteristics for the low-canard configuration are examined by analyses of the low-canard flowfield structure and found to be directly attributed to the interaction between the canard vortex and the wing surface. At relatively low angles of attack, the low-canard vortex passes under the wing surface and induces low pressures on the wing lower surface. As angle of attack is increased, the low-canard vortex impacts the wing surface and is split into two distinct vortices.