Deterministic Optimization of Single-Slotted Flaps Using an Automated CFD Workflow

While aerodynamic optimization of wing geometry in cruise flight has been widely investigated, such modifications inevitably alter the aerodynamic characteristics of high-lift devices, which remain essential during take-off and landing regimes. In this context, the present study addresses the influence of flap slot geometry on the aerodynamic characteristics of single-slotted flap configurations. For this reason, a parametrization method is introduced, combining cubic Bézier curves for flap definition with local curvature parameters for the cove region of the airfoil. This approach ensures geometric continuity in the retracted configuration while enabling rigorous control of the deployed flap geometry. The parametrization was integrated into an automated CFD and gradient-based optimization framework, enabling the efficient exploration of six geometric parameters across multiple configurations. The analysis revealed that lip length and the curvature of the flap’s upper surface have the most significant impact on aerodynamic performance, influencing lift generation, flow attachment, and drag reduction. Optimized configurations achieved up to a 7% increase in maximum lift coefficient and a 5% reduction in drag relative to the baseline geometry. These results highlight the potential of precise geometric control of flap slots to enhance aerodynamic efficiency, particularly in low-speed regimes relevant to take-off and landing. The proposed methodology establishes a foundation for advanced parametrization and optimization strategies for multi-element airfoil configurations and next-generation high-lift systems.