Experimental study on the flowfield of a delta-canard-configuration with deflected leading edge

The turbulent flowfield above the wing of a delta-canard-configuration at moderate (α= 15°) and high (α = 24°) angle of attack was measured at a Re-number of 0.97-10⁶ in a wind tunnel by hotwire anemometry. Leading edge flap settings of η_l.e. = 0° and η_l.e. = -20° were used. At moderate angle of attack and deflected leading edge flap a strong vortex originates from the side edge of the non-deflected inboard wing leading edge part. This inboard wing vortex is located close to the fuselage. It is a dominant flow feature and forms the center of the vortical flow separating from the wing surface. The separation line is clearly different from the leading edge flap hinge line. At high angle of attack the flow separates at the leading edge for both the non-deflected and deflected leading edge case. The resulting leading edge vortex is subject to breakdown close to the apex. In case of the deflected leading edge, the interaction of inboard wing vortex and leading edge vortex results in decreased downstream expansion of the burst vortex, also reducing turbulence intensity levels.