High-lift simulations of slotted, natural-laminar-flow airfoils with drooped leading edge

A computational study was performed to determine the optimal drooped leading edge configuration for a high-lift system compatible with a slotted, natural-laminar-flow airfoil specially designed for a commercial transport. Morphing technology was applied to mitigate abrupt wing-stall characteristics by increasing the radius and bluntness of the main-element’s leading edge. As a result, significantly higher overall maximum lift coefficients were obtained. A previous aft-element optimization for an SNLF airfoil designed for business jets, referred to in this paper as non-optimized, was found to be unsuitable for the system studied herein due to high-lift results showing significant signs of wake bursting. A constant slot-width proved beneficial for a high-lift configuration using morphing technology. Detrimental pressure peaks caused by the sharp curvature of the flap-like drooped leading edge’s upper surface led to compressible stall. This insight on why morphing technology has a superior performance was provided by surface pressure distributions.