Mahesh Hegde
Independent Researcher
India
Abstract
The performance evaluation of vertical axis wind turbines (VAWTs) in low-wind regions presents unique engineering challenges and opportunities, particularly in regions where average wind speeds fall below 5 m/s. This manuscript investigates rotor configurations, aerodynamic profiles, and control strategies appropriate for VAWTs operating under low-wind conditions, using technologies and methods established up to 2016. Two prototype VAWT models—a Savonius–Darrieus hybrid rotor and a helical Darrieus rotor—were fabricated and instrumented to measure torque, rotational speed, and electrical power output. Computational fluid dynamics (CFD) simulations employing Reynolds-averaged Navier–Stokes (RANS) models were conducted to predict flow fields and performance metrics. Field experiments were carried out at two low-wind test sites with average annual wind speeds of 3.2 m/s and 4.1 m/s, respectively. The hybrid rotor achieved a peak coefficient of performance (CP) of 0.24 at 4 m/s, while the helical rotor reached 0.22 under identical conditions. Control strategies based on passive pitch adjustment and variable-resistance electrical loading were demonstrated to enhance startup behavior and energy capture in wind speeds between 2 and 5 m/s. Results indicate that VAWTs with optimized blade profiles and passive control mechanisms can achieve meaningful energy yields in low-wind areas, providing sustainable power solutions for off-grid and microgrid applications. (Approx. 180 words)
KeyWords
vertical axis wind turbines; low-wind areas; Savonius–Darrieus hybrid; helical Darrieus; coefficient of performance; passive control; CFD; renewable energy
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