Vertical-Axis Wind Turbine Clusters: Effect of Streamwise Spacing, Number of Blades and Angle of 6-Turbine Clusters

Wind energy is a clean, renewable, and sustainable resource that plays a key role in reducing carbon emissions and decreasing reliance on fossil fuels. Vertical Axis Wind Turbines (VAWTs) offer an efficient solution for harnessing wind energy, especially in urban environments or regions with low wind speeds. The present study explores the aerodynamic efficiency of H-type Vertical Axis Wind Turbine (VAWT) clusters in power generation and wake interactions by examining the influence of blade count, streamwise spacing, and angular staggering. We integrate the actuator line method (ALM) with large eddy simulation (LES) for accurate performance analysis, making the design and optimization of wind turbines more effective and feasible. This study examines various cluster configurations, including three and four-bladed turbines, respectively, with 2D and 3D streamwise spacings and angular offsets of 20°, 30°, and 45°. Power coefficients (Cp) and near-wake flow characteristics are evaluated using velocity probe measurements. The highest performance is exhibited by the 30° angular staggering and 3D streamwise spacing turbine groups. In contrast, the 20° staggering configurations, particularly with 2D spacing, experiences significant performance losses of up to 51.1% caused by intense wake interactions. Probe measurements shows that turbine alignment relative to upstream pressure zones plays a critical role in performance.