Blade design considerations of small wind turbines: From classical to emerging bio-inspired profiles/shapes

Abstract

The utility of small wind turbines (SWTs) covering horizontal and vertical-axis types as off-grid, standalone, and decentralized energy supplement systems has gained market attention. Such turbines primarily operate at low Reynolds number ( Re) and low tip speed ratio ( λ) conditions. Under such circumstances, the design, development, and testing of SWTs have become a tedious task, mainly due to the lack of precise aerodynamic knowledge of SWT. The present article reviews the fundamental aspects of SWT, including airfoil selection criteria, blade design, and aerodynamic improvement through passive flow control and augmentation techniques. The article also reports several classes of potential airfoils that can be employed in the design of SWTs. The airfoils considered operate mainly in the range of Re = 0.3 x 105 to 3 x 105 and λ = 0.5 to 6. Besides the classical approach, the article showcases the prospects of several bioinspired profiles/shapes that are meant for SWTs operating at low Re and λ conditions. Towards the end, various design constraints and applicability of SWTs are summarized.

Nature-Inspired Designs in Wind Energy: A Review

“…In the realm of biomimetics, Roy et al [48] contributed significantly to wind turbine research by comprehensively reviewing the application of bio-inspired tubercles on horizontal axis wind turbine (HAWT) blades, highlighting their potential to enhance aerodynamic performance, especially in post-stall regimes and varying wind conditions. Siram et al [49] reviewed small wind turbines (SWTs), particularly for offgrid and decentralized energy systems, emphasizing their operation under low Reynolds number and tip speed ratio (TSR) conditions. It addresses key aspects like airfoil selection, blade design, and aerodynamic enhancements, including bio-inspired profiles, suitable for low-Re and low-k SWTs.…”