Abstract
This paper presents a computational study on the effect of the variable pitch angle and the tip speed ratio on the performance of a small vertical-axis wind turbine. By conducting two-dimensional unsteady computational fluid dynamics simulations using RNG k-ε, Realizable k-ε, and SST k-ω models, the power and torque of the vertical-axis wind turbine and the flow around the straight blades were analyzed. The numerical simulation results were validated using wind tunnel experimental data. The results of both of both the numerical simulations and experiments showed that the vertical-axis wind turbine with variable-pitch blades had better performance than one with fixed-pitch blades. The numerical simulation performance using the RNG k-ε turbulence model had good qualitative agreement with the experiment. The numerical simulation using the SST k-ω model could capture the presence of a vortex on a blade when dynamic stall occurred at a low tip speed ratio.
