The effect of a 70 deg swept canard on the leading-edge vortices of a 70 deg swept delta wing during dynamic pitching

Abstract

The effect of a canard on delta wing vortices was investigated in the 2 ft x 3 ft water tunnel at Wichita State University. It is well known that the leading-edge vortices generated by a delta-shaped wing greatly enhance a vehicle's performance at high angles of attack. In this experiment, a 70 swept canard was placed in front of a 70 deg swept main delta wing. Dye flow visualization was used to observe the vortex breakdown location during dynamic pitch-up and pitch-down motion with varying pitch rates. Compared to the no canard configuration, results showed that there was a delay in vortex breakdown due to the presence of the canard and the dynamic pitch motion. The most favorable delay was obtained when the canard was located closest to the main delta wing and the model was pitched up at a fast rate or pitched down at a slow rate. Complete vortex breakdown on the main delta wing occurred at 53 deg for the static case without canard. In comparison, complete vortex breakdown did not occur until 90 deg when the canard configured delta wing was pitched up at a very fast rate. (Author)