Experimental and numerical investigation of a three-dimensional vertical-axis wind turbine with variable-pitch

• Variable-pitch mechanism boosts the performance of the VAWT.
• Connecting rods cannot be neglected at high TSRs.
• Thicker symmetric airfoils perform better for high solidity VAWTs.
• Symmetric airfoils perform better than airfoils with Camber.

A combined experimental and numerical investigation is carried out to study the performance of a micro vertical-axis wind turbine (VAWT) with variable-pitch. Three-dimensional numerical simulations are essentially employed, for the VAWT involves a low aspect ratio (AR) three straight blades with struts. The performance of the VAWT is experimentally measured using a wind tunnel, while large eddy simulation (LES) with dynamic smagorinsky subgrid scale (SGS) model is employed to help understand the associated flow structure. The effects of wind speed, turbulence intensity, airfoil shape, and strut mechanism with and without variable-pitch on the performance of the turbine are carefully assessed, both experimentally and numerically. The accuracy of the SGS model in predicting the laminar–turbulent transition is also examined.