Variable pitch control in vertical axis wind turbines: A modified double multiple stream tube (DMST) modelling approach

This study refines a low-fidelity aerodynamic model for vertical axis wind turbines (VAWTs) by integrating variable pitch (VP) control into a modified Double Multiple Stream tube (DMST) framework. The VP strategy dynamically adjusts blade pitch to maintain an optimal angle of attack ( AoA ) of about 16°, chosen to maximize lift while avoiding flow separation. Validation against fixed-pitch DMST benchmarks confirms the model’s accuracy in predicting aerodynamic coefficients. Compared to fixed-pitch designs, VP control reduces AoA fluctuations, particularly at low tip speed ratios ( TSRs ), confining variations within ±15°. This mitigates dynamic stall, lowers unsteady aerodynamic loads, and produces smoother torque profiles, enhancing mechanical stability. Performance analysis shows that a VP-enabled single-bladed VAWT achieves peak power coefficients above 1.07 at TSR = 6, i.e. 200% higher than fixed-pitch cases and with significant improvements across TSRs from 2 to 10. However, benefits decline as blade count increases due to aerodynamic interference and reduced pitch modulation bandwidth. Cross-validation of regression models indicates that rotor speed and target AoA are the dominant predictors, AoA demonstrating a consistent explanatory structure and satisfactory predictive accuracy across metrics such as adjusted R², AIC, and BIC. The findings demonstrate that variable-pitch control can substantially enhance the energy yield and reliability of compact wind systems, contributing to sustainable energy transition. • Variable pitch/VP stabilizes Angle of Attack, boosting lift and reducing dynamic stall • Validated DMST model confirms accuracy in aerodynamic performance prediction • VP control smooths torque profiles, enhancing turbine stability and lifespan • Peak power coef. > 1.07 at Tip speed ratio 6 exceed 200% than fixed-pitch turbine • AI-driven analysis identifies dominant interactions influencing performance