Multi-Objective Optimization of a Dual-Mode Airfoil for Enhanced Performance in Natural and Hybrid Laminar Flow Control Operations
Abstract
In this study, we introduce a high-performance, dual-mode sailplane airfoil to offer enhanced performance using Hybrid Laminar Flow Control (HLFC) and reliable performance in Natural Laminar Flow (NLF) conditions. Using boundary layer suction in HLFC mode significantly improves the drag bucket in the climb/cruise phases and maintains improved stall characteristics at high angles of attack. In NLF mode, performance aligns with the renowned DU89 airfoil. The airfoil is designed using a Multi-Objective Genetic Algorithm (MOGA) by minimizing the average cruise and climb drag in the contexts of both, NLF and HLFC. The design variables in the optimization include the onset location of suction, flap deflection angles, and the airfoil parameterization. The optimized airfoil resembles popular NLF sailplane airfoils, with suction starting at 35% of the chord. An average drag reduction of 27% was observed during cruise and climb phases in HLFC mode compared to NLF mode. These attributes make the airfoil a promising candidate for advanced sailplane designs with energy stored in batteries. These designs are expected to improve efficient and high-performance flight characteristics.
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