Evaluating the Performance of an H-Type Wind Turbine: How Stalling Stages and Blade–Vortex Interactions Affect the Turbine?

Abstract The growing integration of renewable energy, especially wind power, in urban settings necessitates the optimization and performance enhancement of small-scale vertical axis wind turbines (VAWTs). The major challenges in VAWT performance enhancement are impediments to self-starting, lower performance, flow instability due to blade wake interactions, and dynamic stability at lower tip speed ratios (TSRs). This work examines two aspects: the numerical investigation of the influence of TSR on the aerodynamic performance of the two-bladed H-rotor, and the analysis of the deep dynamic stall phenomenon involving interaction between blade and shaft vortices. It is observed that fluctuations increase to 2.6 times for the deep stall condition compared to no stall. It is also observed that between no stall and deep stall conditions, there is a significant difference (∼83%) in the peak-to-peak amplitude of the lift coefficient, indicating deterioration in rotor performance as it enters a deep stall. In the downwind zone, the vorticity contour indicates blade–vortex interaction, affirming the reduction in moment and its reduced recovery. The results of Fast Fourier Transform indicate that the peak amplitude decreases by a factor of 1.6 in the downwind zone, signifying the development of stronger vortical structures in the upwind region.