Innovative aerodynamic enhancements for horizontal-axis wind turbines: Design, simulation, and efficiency improvement

This review evaluates recent aerodynamic enhancement strategies for horizontal-axis wind turbines (HAWTs), with emphasis on low-wind-speed operation, simulation fidelity, and experimental validation. A structured literature screening process covering publications from 2020 to 2025 yielded 60 studies for qualitative synthesis after 175 full-text records had been assessed for eligibility. The review concentrates on HAWT-specific studies and organizes the evidence around four themes: airfoil and blade-shape refinement, twist and chord redistribution, guide-ring or tip-device additions, and hybrid simulation frameworks combining blade element momentum (BEM), computational fluid dynamics (CFD), and machine-learning surrogates. Across the reviewed studies, twist-angle refinement and blade-shape tailoring repeatedly improved aerodynamic performance under study-specific operating conditions, while ANN-assisted surrogates reduced design-cycle cost for small-scale turbines. However, the reported gains are not directly comparable because they were obtained for different scales, Reynolds numbers, turbulence levels, and validation protocols. The synthesis therefore indicates that future HAWT development should prioritize physically consistent model selection, uncertainty-aware validation, and integrated assessment of aerodynamics, structural feasibility, manufacturability, and lifecycle performance.