A CFD Analysis of the Geometrical Optimization of Slotted Airfoils by Using the RANS k-ω SST Turbulence Model

Abstract

Lift generation is a fundamental prerequisite for sustained aircraft flight. Maintaining attached flow over a significant portion of the wing surface is crucial to achieving this. Low aircraft velocities necessitate higher lift coefficients for sufficient lift generation by attaining a higher angle of attack. However, a higher α also causes flow separation. A stall occurs when the angle of attack reaches its critical value, the stalling angle of attack at which the lift coefficient reaches its maximum. While flaps and slats improve flow to some degree, there are limitations. This study investigates the influence of slotted airfoils on aerodynamic performance. A NACA 2412 airfoil was divided into three, four, and five elements. The lift and drag coefficients of these slotted airfoils and plain NACA 2412 were evaluated using computational fluid dynamics (CFD) with a Reynolds number of 2.2×106 at various angles of attack. To further investigate, the five-element airfoil was modified into additional configurations with 10% gradual dimensional variations. The shear stress transport (SST) model achieved a remarkable clmax with a 53.59% increment at a stall angle of 22° compared to the plain NACA 2412. This study emphasizes the importance of slotted airfoils in enhancing aerodynamic performance by delaying flow separation to achieve optimal lift efficiency. The insights from this study on slotted airfoils have significant practical applications in aerospace. Incorporating slotted airfoils, especially the five-element configuration, can enhance lift-to-drag ratios, improving aircraft performance during takeoff and landing. This delay in flow separation increases stability and control, reducing stall risks and enhancing flight safety. Additionally, the improved aerodynamic performance can lead to economic efficiencies by lowering fuel consumption and operating costs. For high-performance aircraft, these findings inform advanced wing designs, addressing high-speed and maneuverability needs. The research also offers a foundation for future studies on slotted airfoil designs and holds educational value for teaching aerodynamics principles. Implementing these findings could lead to substantial advancements in aircraft design and performance across the aviation industry.